; ****************************************************************************** ; SX MultiMedia Card (MMC) VIRTUAL PERIPHERAL AUDIO DEMO ; (C) Copyright 1997-2000 Scenix Semiconductor ; ; ; Length: 476 bytes (total) ; Authors: Craig Webb, Andrian Kouznetsov ; Written: 97/03/10 to 00/10/30 ; ; This program implements six virtual peripherals on Scenix's SX28/52 ; DEMO board for demonstrating MultiMedia Card (MMC) external memory ; storage playing its contents as a .WAV file through the audio plug-in PCB. ; The MMC is accessed through a high level command interpreter subroutine ; peripheral that controls the MMC by way of an SPI subroutine interface ; peripheral. Data coming in from the MMC is stored in a circular buffer ; as it awaits output through the audio harware. The program uses timer ; clock virtual peripheral in conjunction with a pulse width modulation ; (PWM) virtual peripheral for output of the stored MMC data as streamed ; audio samples, and also uses a sigma-delta A/D virtual peripheral to ; sample external signals that can then be written to the MMC. ; ; 1) MMC command interpreter interface ; 2) SPI interface subroutine(s) ; 3) Circular storage buffer ; 4) Timer routine ; 5) Pulse-Width Modulated (PWM) outputs (2) ; 6) Adjustable 8-15-bit Analog-to-Digital Converter (ADC) (1) ; ; These latter four of these virtual peripherals take advantage ; of the SX's internal RTCC-driven interrupt and operate ; in the background while the main program loop is executing. ; ;****************************************************************************** ; Program Notes: ; ; -Be careful that the SX SPI port pins are initialized when inserting or ; removing the MMC, oherwise peculiar card states can result (in which ; case the MMC should be completely removed and powered off, and then ; the SYNCHRONIZATION and INITIALIZATION routines must be run again). ; ; -if the program does encounter any MMC communication error, it is best ; to repeat the INITIALIZATION routine, and occasionally the ; SYNCHRONIZATION routine also. ; ;============================================================================== ; ;******************************* Program Variables *************************** ; ; ;****** Assembly Options ; pcb_revision = 0 ;0 or 1 ;PCB revision 1.x compiler = 0 ;0 or 1 ;0=SX-Key, 1=SXIDE stereo = 0 ;0 or 1 ;set =1 for stereo PCM data chip_type = 1 ;0 or 1 ;0=SX18/28, 1=SX52 include_adc = 0 ;0 or 1 ;0=adc routine not included ; ;****** Adjustable Paramaters ; sample_freq = 11025 ;6512-44100 ;sampling rate of .wav file MMC_size = 4 ;1-128 ;storage size of MMC card resolution = 8 ;8-15 ;adc resolution (8-15 bits) pwm0_init = 80h ;0-FFh ;initial pwm0 voltage pwm1_init = 80h ;0-FFh ;initial pwm1 voltage ; ;****** Program Variables ; int_period = 40+(include_adc*20)+6 ;minimum + main routine allowance sx_freq_factor = 1 ;this is a time delay scaling factor, ; for SX running at 50MHz(=1), 100MHz (=2) ; ;****** Program Constants & Dependent Variables ; ;sample_freq= $380 @ 11,025Hz mono, with xtal=50MHz, with adc on samp_freq = $380*int_period/66*sample_freq/11025 ;sets the audio PCM sample rate IF stereo=1 samp_freq = samp_freq*2 ;stereo needs twice the sample output rate ENDIF IF MMC_size<16 end_of_mem = MMC_size<<4-3 ;last bank of mmc memory blocks ELSE ; for MMC cards >16Meg end_of_mem = MMC_size>>4-3 ;last bank of mmc memory blocks ENDIF end_of_mem = $37 ; or end of audio sample (comment this if needed) IF compiler=0 ;assembler directive (for SX-Key) freq 50_000_000*sx_freq_factor ;default clock rate: 50 MHz ENDIF ; ;***SPIX timing delays: ;spix_rate = (1 + (3 * ( sx_freq_factor - 1))) spix_rate = sx_freq_factor ;rate factor for SPIX.MMC ; (may need to be trimmed for different SX clock rates) sync_duration = 10 ;?-255 ;MMC SYNCHRONIZATION function duration cmd1_resp_wait = $80 * sx_freq_factor ;?-128 ;initialization (CMD1) response wait duration cmd1_delay1 = $8 ;* sx_freq_factor ;?-128 ;initialization (CMD1) internal loop delay cmd1_delay2 = $10 ;* sx_freq_factor ;?-128 ;initialization (CMD1) internal loop delay cmd1_delay3 = $80 * sx_freq_factor ;?-128 ;initialization (CMD1) internal loop delay resp_r1_delay = 32 * sx_freq_factor ;2-255 ;delay for a RESPONSE from MMC blk_rd_delay1 = 1 * sx_freq_factor ;?-255 ;delay for MMC initial block read preparation " written blk_rd_wait = 20 * sx_freq_factor ;?-255 ;read wait time MMC incoming data bytes blk_wr_delay = 20 * sx_freq_factor ;?-255 ;delay for MMC initial block write preparation ; option_init = %10001000 ;bits: 1=RTCC@01h|0=int_en|0=RTCC_internal|x|psa(1=WDT)|ps(2-0) resolution = resolution-8 ;8-15 ;adc resolution (8-15 bits) ; mmc_blk_size = 512 ;block size for reading/writing MMC (in SPI mode) mmc_buffsize = 32 ;MMC read/write buffer size: must be =(2^n)*16, n=0,1,2(,3 for SX52) ; (only 16 and 32 have been tested) ;****** Assembler Directives ; ; DEVICE turbo ID 'MMCAudio' ;program ID label RESET reset_entry ;set reset/boot address ;******************* Configuration DATA and I/O pins ************************* ; ;****** Port definitions ; RA_IO = %0010 ;port A I/O directions RA_init = %1111 ;port A initial output states ;--------------- ;Pin assingment for SPI_X interface spix_clk_pin EQU RA.3 ;SPI clock output spix_out_pin EQU RA.2 ;SPI-Master-Out-Slave-In spix_in_pin EQU RA.1 ;SPI-Master-In-Slave-Out spix_cs_pin EQU RA.0 ;SPI device select ;=============== RB_IO EQU %10111111 ;port B I/O directions RB_init EQU %11111111 ;port B initial output states analog_port1 EQU RB ;--------------- LEDs EQU RB ;individual LED outputs ; await_button EQU LEDs.3 ;await button signal init_err EQU LEDs.2 ;signals initialize MMC error read_err EQU LEDs.1 ;signals read from MMC error write_err EQU LEDs.0 ;signals write to MMC error ;--------------- IF pcb_revision=0 ;--------------- RC_IO EQU %11110110 ;port C I/O directions RC_init EQU %11111111 ;port C initial output states analog_port2 EQU RC ;--------------- ;note: make duplicate changes in "analog_buff" pwm0_pin EQU RB.6 ;Pulse width mod. PWM0 output pwm1_pin EQU RC.3 ;Pulse width mod. PWM1 output adc0_in_pin EQU RC.2 ;ADC0 input pin adc0_out_pin EQU RC.0 ;ADC0 output/calibrate pin ;--------------- ELSE ;pcb_revision=1.1 ;--------------- RC_IO EQU %11111010 ;port C I/O directions RC_init EQU %11111111 ;port C initial output states analog_port2 EQU RC ;--------------- ;note: make duplicate changes in "analog_buff" pwm0_pin EQU RB.6 ;Pulse width mod. PWM0 output pwm1_pin EQU RC.2 ;Pulse width mod. PWM1 output adc0_in_pin EQU RC.1 ;ADC0 input pin adc0_out_pin EQU RC.0 ;ADC0 output/calibrate pin ;=============== ENDIF ;revision ; ;******************************** MMC_SPIX RAM **************************** ORG $0E ;global ram next_samp_ptr DS 1 ;points to next sample in buffer mmc_temp_data DS 1 ;temporary storage to move the data ; between the SX RAM banks ;=============== ;SPIX and MMC make use of the same RAM bank mmc_spix_ram ORG $10 ;MMC/SPI control register bank ; mmc_status ds 1 ;MMC driver status byte ;--------- spix_busy equ mmc_status.7 ;Busy bit set by SPIX VP to HIGH when byte ;transfer (SPI) is in progress mmc_busy equ mmc_status.6 ;set when the MMC is in BUSY state. Used in WRITE MODE mmc_read_write_data equ mmc_status.5 ;indicates that BLOCK READ/WRITE cycle is in progress mmc_error equ mmc_status.4 ;any error in data transfer ;MMC_R1 and MMC_R2 contain the error message mmc_no_response equ mmc_status.3 ;no response R1 was received ;within required time mmc_data_error equ mmc_status.2 ;data error token received ;during Block Read/Write command mmc_no_data equ mmc_status.1 ;no data block received from MMC mmc_wrong_command equ mmc_status.0 ;Set by the commnds decoder, indicates not supported command ;======== mmc_cmd ds 1 ;mmc command - 6 bytes mmc_addr_b3 ds 1 mmc_addr_b2 ds 1 mmc_addr_b1 ds 1 mmc_addr_b0 ds 1 mmc_cmd_crc ds 1 mmc_r1 ds 1 ;mmc response - 2bytes mmc_r2 ds 1 mmc_temp ds 1 ;temporary storage for MMC driver mmc_temp1 ds 1 mmc_temp2 ds 1 mmc_data_pointer ds 1 ;pointer to the current address ;of the SX data RAM ;SPIX data spix_data_io ds 1 ;one-byte I/O data buffer/shift register spix_temp ds 1 ;temporary storage spix_shift_counter ds 1 ;I/O shift counter ;------------------------ ; org 30h ;bank4 variables analog = $ ;pwm and ADC bank & timer ; analog_buff1 DS 1 ;analog output buffer analog_buff2 DS 1 ;analog output buffer IF pcb_revision=0 ;--------------- pwm0_out EQU analog_buff1.6 ;pwm0 buffer pwm1_out EQU analog_buff2.3 ;pwm1 buffer adc0_out EQU analog_buff2.0 ;adc0 out buffer ;--------------- ELSE ;--------------- pwm0_out EQU analog_buff1.6 ;pwm0 buffer pwm1_out EQU analog_buff2.2 ;pwm1 buffer adc0_out EQU analog_buff2.0 ;adc0 out buffer ;--------------- ENDIF pwm0 DS 1 ;pwm0 - value pwm0_acc DS 1 ; - accumulator pwm1 DS 1 ;pwm1 - value pwm1_acc DS 1 ; - accumulator ; adc0_lo DS 1 ;adc0 - value low byte adc0_hi DS 1 ; " high byte adc0_count_lo DS 1 ; - real-time count (lo) adc0_count_hi DS 1 ; - " " " (hi) adc0_acc_lo DS 1 ; - accumulator (lo) adc0_acc_hi DS 1 ; - " (hi) ; freq_low ds 1 ;frequency value low byte freq_high ds 1 ;frequency value high byte freq_accl ds 1 ;frequency accumulator low byte freq_acch ds 1 ;frequency accumulator high byte ;=============== mmc_data_ram ORG $70 ;MMC read/write data buffer(length of buffer=mmc_buffsize) ; (e.g. in the case of 32 bytes it will occupy banks $50 & $70) ;**************************** INTERRUPT CODE ******************************* ; ORG 0 ; ;****** Virtual Peripheral: TIMER/FREQUENCY OUTPUT ; ; This routine adds a programmable value to a 16-bit accumulator (a pair of ; two 8-bit registers) during each pass through the interrupt. It then ; copies the value from the high bit of the accumulator to the ; appropriate output port pin (LED, speaker, etc.) ; ; Input variable(s) : timer_low,timer_high,timer_accl,timer_acch ; freq_low,freq_high,freq_accl,freq_acch ; Output variable(s) : LED port pin, speaker port pin ; Variable(s) affected : timer_accl, timer_acch, freq_accl, freq_acch ; Flag(s) affected : none ; Size : 1 byte + 10 bytes (per timer) ; Timing (turbo) : 1 cycle + 10 cycles (per timer) ; :frequency bank analog ;switch to timer (& adc/pwm) bank ; clc ;only needed if CARRYX=ON add freq_accl,freq_low ;adjust freq's accumulator CLR W ;zero W reg. SNC ;did we get an overflow in low byte? MOV W,#1 ;if so, prepare to adjust high byte ADD W,freq_high ; (freq = 16 bits long) SZ ;if overflow for adjustment, skip ahead ADD freq_acch,W ;adjust high byte of accumulator SC ;skip ahead if timer triggered JMP :done ;if not, jump ahead to end :circ_buffer MOV W,next_samp_ptr ;load sample pointer MOV FSR,W ; for indirect addressing MOV W,ind ;load next sample BANK analog ;reset bank to analog CLRB FSR.7 ; and make sure we're in lower 128reg. block IF stereo=0 MOV pwm0,W ;convert it to audio MOV pwm1,W ; " ELSE SB next_samp_ptr.0 ;is this left channel? MOV pwm0,W ;yes, send out out left SNB next_samp_ptr.0 ;otherwise, if it's right channel MOV pwm1,W ; send it out right ENDIF INC next_samp_ptr ;advance pointer IF chip_type=0 ;SX18/28 MOV W,#buff_size*2+mmc_data_ram ;last address ELSE ;SX52 MOV W,#mmc_data_ram+mmc_buffsize ;last address ENDIF MOV W,next_samp_ptr-W ;test for end of buffer MOV W,#mmc_data_ram ;pre-load new offset in case SNZ ;if not at end, skip ahead MOV next_samp_ptr,W ;reset to start of buffer IF chip_type=0 MOV W,#$10 ;keep to odd banks for SX18/28 OR next_sample_ptr,W ; " ENDIF :done ; ;***** Virtual Peripheral: Pulse Width Modulators ; ; These routines create an 8-bit programmable duty cycle output at the ; respective pwm port output pins whose duty cycle is directly proportional ; to the value in the corresponding pwm register. This value is added to an ; accumulator on each interrupt pass interrupt. When the addition causes a ; carry overflow, the ouput is set to the high part of its duty cycle. ; These routines are timing critical and must be placed before any ; variable-execution-rate code (like the UART, for example). ; ; Input variable(s) : pwm0,pwm0_acc,pwm1,pwm1_acc ; Output variable(s) : pwm port pins ; Variable(s) affected : port_buff, pwm0_acc, pwm1_acc ; Flag(s) affected : none ; Size : 3 bytes + 4 bytes (per pwm) ; + 4 bytes shared with adc code (see below) ; Timing (turbo) : 3 cycles + 4 cycles (per pwm) ; + 4 cycles shared with adc code (see below) ; ;:set_analog bank analog ;switch to adc/pwm bank clr analog_buff1 ;zero pwm output buffer clr analog_buff2 ;zero pwm output buffer :pwm0 add pwm0_acc,pwm0 ;adjust pwm0 accumulator snc ;did it trigger? setb pwm0_out ;yes, toggle pwm0 high :pwm1 add pwm1_acc,pwm1 ;adjust pwm1 accumulator snc ;did it trigger? setb pwm1_out ;yes, toggle pwm1 high ;:update_analog MOV analog_port1,analog_buff1 ;update cap. charge/discharge pins ; MOV analog_port2,analog_buff2 ;update cap. charge/discharge pins :end_pwms ; IF include_adc=1 ;is this to be assembled in? ;***** Virtual Peripheral: Bitstream Analog to Digital Converters ; ; These routines allow an 8-bit value to be calculated which corresponds ; directly (within noise variation limits) with the voltage (0-5V) present ; at the respective adc port input pins. These routines are timing critical ; and must be placed before any variable-execution-rate code (like the UART, ; for example). The currently enabled routine (version A) has been optimized ; for size and speed, and RAM register usage, however a fixed execution rate, ; yet slightly larger/slower routine (version B) is provided in commented ; (disabled) form to simplify building other timing-critical virtual ; peripheral combinations (i.e. that require fixed rate preceeding code). ; Note: if version B is selected, version A must be disabled (commented) ; ; Input variable(s) : adc0_in_pin,adc0_acc_lo/hi,adc0_count_lo/hi ; Output variable(s) : analog_port1,analog_port2,analog_buff1,analog_buff2 ; Variable(s) affected : adc0_out,adc0_acc_lo/hi,adc0_count_lo/hi ; Flag(s) affected : none ; Size : 20 + 4 bytes shared with pwm code (see above) ; Timing : 5 cycle shared with pwm code (see above) + ; (a) [>99.5% of time] 15 cycles ; (b) [<0.5% of time] 20 cycles ; ;*** If the PWM routines are removed, the following 2 instructions must ;*** be enabled (uncommented) for the ADC routine to function properly: ; bank analog ;switch to adc/pwm bank :adc0 SB adc0_in_pin ;get current status of adc0 SETB adc0_out ;complement input to output SNB adc0_in_pin ; " CLRB adc0_out ; " SB adc0_in_pin ;check if adc0 triggered? INCSZ adc0_acc_lo ;if so, incr. 16-bit accumulator DEC adc0_acc_hi ; adjusting high byte as necessary INC adc0_acc_hi ; but making sure not to :adj_count INCSZ adc0_count_lo ;adjust 16-bit counter DEC adc0_count_hi ; by skipping this instr. INC adc0_count_hi ; when low byte overflows :check_trig SB adc0_count_hi.resolution ;sample ready? JMP :done_adcs ;if not, exit adc routine :adc_ready MOV adc0_lo,adc0_acc_lo ;yes, copy new value MOV adc0_hi,adc0_acc_hi ; into adc0 registers CLR adc0_count_hi ;clear count (low already=0) CLR adc0_acc_lo ;clear accumulator (low) CLR adc0_acc_hi ;clear accumulator (high) :done_adcs ENDIF ;whether to include adc or not :update_analog MOV analog_port1,analog_buff1 ;update cap. charge/discharge pins MOV analog_port2,analog_buff2 ;update cap. charge/discharge pins MOV W,#-int_period ;interrupt every 'int_period' clocks RETIW ;exit interrupt :end_int ; ;****** End of interrupt sequence ;=========================================================================== ; ;***************************** PROGRAM DATA ******************************** ; ;****************************** SUBROUTINES ******************************** ; Sine_Table JMP PC+W ;Lookup sine value (32 bytes) RETW 128,153,174,199,219,234,246,254,255,254,246,234,219,199,174,153 RETW 128,103,79,57,37,22,10,2,0,2,10,22,37,57,79,103 ;Sine_Table_16 RETW 0,9,37,79,128,176,218,246,255,246,218,176,128,79,37,9 ; ;****************************** ;*** 8-BIT SPI Master VP - SPIX ;****************************** ;SPIX DATA TRANSFER ;================== ; ;***Send the byte spix_send bank mmc_spix_ram ;select SPIX RAM bank setb spix_busy ;set the bit indicating that ;SPIX started data transfer mov spix_shift_counter,#$08 ;set number of shifts spix_send_loop ;CLK_HIGH clrb spix_clk_pin ;set CLK_LOW movb spix_out_pin,spix_data_io.7 ;shift data out. CLK_LOW rl spix_data_io ;CLK_LOW mov spix_temp,#spix_rate ;transfer rate delay spix_loop2 djnz spix_temp,spix_loop2 ;CLK_LOW setb spix_clk_pin ;set CLK - HIGH mov spix_temp,#spix_rate ;transfer rate delay spix_loop3 djnz spix_temp,spix_loop3 ;CLK- HIGH djnz spix_shift_counter,spix_send_loop ;check the bit counter clrb spix_busy ;exit if done setb spix_out_pin ret ;get the byte spix_get bank mmc_spix_ram ;select SPIX RAM bank setb spix_busy ;prepare to start mov spix_data_io,#$ff ;preset all bits high STC ;including carry bit mov spix_shift_counter,#$08 ;set number of shifts spix_get_loop ;CLK_High clrb spix_clk_pin ;set CLK_LOW rl spix_data_io ;CLK_LOW IF sx_freq_factor>1 ;100 MHZ? mov spix_temp,#spix_rate ;transfer rate delay spix_loop6 djnz spix_temp,spix_loop6 ; while CLK_LOW ENDIF SB spix_in_pin ;if new bit=1, then do nothing CLRB spix_data_io.0 ; otherwise, clear it accordingly setb spix_clk_pin ;set CLK_HIGH IF sx_freq_factor>1 ;100 MHZ? mov spix_temp,#spix_rate ;transfer rate delay spix_loop8 djnz spix_temp,spix_loop8 ;while CLK_High ENDIF djnz spix_shift_counter,spix_get_loop;check the bit counter setb spix_out_pin ;exit if done clrb spix_busy ret ;End of SPIX VP ;*********************** ; ;*** SPIX port initialization ; spix_init setb spix_clk_pin setb spix_out_pin setb spix_cs_pin RET ;*** Set MMC data address = 0 zero_MMC_addr CLR mmc_addr_b3 ;set the block address to read (hi byte first) CLR mmc_addr_b2 ; " CLR mmc_addr_b1 ; " CLR mmc_addr_b0 ; (lo byte last: always = 0 since 512 bytes/block) RET ;*********************** MMC COMMAND INTERPRETER ********************** ; ;FUNCTIONS are not MMC card commands, but sequences of the commands. ;The MMC VP currently implements four separate FUNCTIONS ; - synchronize ; - initialize ; - read the data block ; - write the data block mmc_synchronize equ $FF ;send 80 SPI_clk signals for initial synchronization mmc_initialize equ $FE ;card initialization procedure ; flow chart (exept for synchronization) mmc_block_read_command equ $FD ;Complete implementation of the block read flow chart ;Send the Read Block Command and set the ;mmc_read_write_data flag in the MMC_STATUS byte ;The MMC /CS line is left active (LOW) until the data ;are read. Get the data block from MMC and ;finishes the read block cycle by setting MMC /CS mmc_block_write_command equ $FA ;complete implementation of the block writing ; ;MMC COMMANDS. ;Implemented MMC commands are used as FUNCTION calls ;Other commands listed here (but currently unimplemented) are presented ; mainly for reference. These commands are described in detail in the MMC manual. mmc_go_idle_state equ $40 ;CMD0 ;these three command are used as a part mmc_send_op_cond equ $41 ;CMD1 ;of INITIALIZE function mmc_set_blocklen equ $50 ;CMD16 mmc_read_single_block equ $51 ;CMD17 mmc_write_block equ $58 ;CMD24 ;----------------------- ;MMC commands currently NOT implemented: ;mmc_send_status equ $4d ;CMD13 assuming that status data come in the ;R2 bytes ;mmc_send_csd equ $49 ;CMD9 ;mmc_send_cid equ $4a ;CMD10 ;mmc_program_csd equ $5b ;CMD27 ;mmc_set_write_prot equ $5c ;CMD28 ;mmc_clr_write_prot equ $5d ;CMD29 ;mmc_send_write_prot equ $5e ;CMD30 ;mmc_tag_sector_start equ $60 ;CMD32 ;mmc_tag_sector_end equ $61 ;CMD33 ;mmc_untag_sector equ $62 ;CMD34 ;mmc_tag_erase_group_start equ $63 ;CMD35 ;mmc_tag_erase_group_end equ $64 ;CMD36 ;mmc_untag_erase_group equ $65 ;CMD37 ;mmc_erase eque $66 ;CMD38 ;mmc_crc_on equ $67 ;CMD59 ;******************** MMC Subroutines ********************************* ; ;*** MMC Wait ;Sometimes a delay is needed for internal MMC processes mmc_long_wait MOV W,#$FF ;longest delay mmc_wait MOV mmc_temp1,W ;selectable delay (loaded in W prior to call) mloop49 mov mmc_temp,#$FF ;set wait cycles counter mloop69 djnz mmc_temp,mloop69 ;inner delay loop djnz mmc_temp1,mloop49 ;outer delay loop ret ;exit ;*** MMC Send "DUMMY" Bytes ;This subroutine generates a number of DUMMY byte transfer cycles on the SPI bus. ;The number of cycles should be specified in MMC_TEMP prior to the call. ;These dummy cycles are required by the MMC card data transfer protocol. ; mmc_delay bank mmc_spix_ram call spix_get djnz mmc_temp,mmc_delay ret ;*** MMC Send Command ;This Subroutine sends a 6 byte MMC command string starting with the MMC_CMD byte ;and finishing by CRC byte ; mmc_cmd_send bank mmc_spix_ram ;select SPIX RAM bank mov mmc_temp,#mmc_cmd mmc_loop2 mov fsr,mmc_temp mov w,ind ;load next COMMAND byte to ;the SPIX I/O buffer using index addressing mode mov spix_data_io,w call spix_send ;send the byte inc mmc_temp cjne mmc_temp,#(mmc_cmd + 6),mmc_loop2 setb spix_out_pin ;loop until all six bytes sent ret ;*** MMC Get Response R1 ;Get the response byte from the MMC. Wait for the response R1 for x=mmc_r1_wait_cycles ;byte cycles. If the R1 is not recieved or R1 is not $00, set the error flag. ;Number of wait cycles is recommended to be 2, but here we use 32 for safety. ;The routine can return two errors: (1) no response at all, (2) non zero response ; mmc_r1_get bank mmc_spix_ram ;select the RAM bank mov mmc_r1,#$ff ;initialize the byte to FF mov mmc_temp,#resp_r1_delay ;set delay counter mmc_loop3 call spix_get ;read the byte cjne spix_data_io,#$FF,mmc_loop4 ;if the byte is "FF" then repeate ;mmc_r1_wait_cycles times djnz mmc_temp,mmc_loop3 setb mmc_no_response ;no response ret mmc_loop4 test spix_data_io ;test if not zero sz setb mmc_error ;set an error flag mov mmc_r1,spix_data_io ret ;******************** MMC Command Function Interpreter ******************* ;This is the MMC command decoder subroutine. This is an optional structure ;The actual commands can be executed separately. The use of this structure ;is to reduce the number of subroutines (i.e. CALLs) and replace them by JMPs ; mmc_execute bank mmc_spix_ram cje mmc_cmd,#mmc_block_read_command,mmc_cmd_block_read cje mmc_cmd,#mmc_block_write_command,mmc_cmd_block_write cje mmc_cmd,#mmc_synchronize,mmc_cmd_synchronize cje mmc_cmd,#mmc_initialize,mmc_cmd_initialize setb mmc_wrong_command mmc_exit ret ;****************************** MMC Functions **************************** ;*** Read Data Block (Function $51) ;upon the reception of this command the MMC will start to access the data block. ;the data will be ready within 1.5 msec ; mmc_cmd_block_read bank mmc_spix_ram ;Select the RAM Bank clrb spix_cs_pin ;set MMC_CS active (LOW) ; mov mmc_temp,#blk_rd_delay1 ;do a DUMMY read cycle delay ; call mmc_delay ; clr mmc_status :do_read mov mmc_cmd,#$51 ;send the BLOCK READ Command call mmc_cmd_send call mmc_r1_get test mmc_r1 ;MMC response is not Zero, exit jnz mmc_read_exit ;******************* Continue Read Cycle, Read The Data ********************* ;Wait for the Start Byte. ;Wait time is set to (mmc_read_wait_cycles * $FF). Total wait time sould be 1.5ms+. mmc_read_data_block bank mmc_spix_ram ;select the RAM bank setb mmc_read_write_data ;await data start byte = $FE mov mmc_temp1,#blk_rd_wait ;load delay value mmc_label40 mov mmc_temp,#$FF ;set wait counter mmc_label41 call spix_get ;wait for data start byte = $FE cje spix_data_io,#$fe,mmc_label42 ;End waiting if Start Byte cjne spix_data_io,#$ff,mmc_label44 ;End waiting if Error Message djnz mmc_temp,mmc_label41 ;inner wait loop djnz mmc_temp1,mmc_label40 ;outer wait loop setb mmc_no_data ;waiting time expiered - error jmp mmc_read_exit ;exit mmc_label44 mov mmc_r2,spix_data_io ;Error message is in R2 setb mmc_data_error ;MMC sent the Data Error Token jmp mmc_read_exit ;the token will be placed in MMC_R2 ;Read MMC Data (if no errors occurred): ;This routine should be used as an example only. It transfers a block of data from MMC card ;placing the data bytes in the data storage buffer. Since the buffer is smaller than the MMC ;block size (i.e. data not being streamed), the 512 bytes coming from the MMC will ;repeatedly overwrite the buffer locations with the data steaming from MMC card. ;At the end of the cycle the last 16 (32) bytes of 512 MMC data block will be located ;in the SX data buffer mmc_label42 mov mmc_temp2,#mmc_blk_size/mmc_buffsize ;set number of cycles mmc_label43 mov mmc_temp,#mmc_buffsize ;set the byte counter and IF chip_type=0 ;SX18/28 MOV W,#buff_size*2+mmc_data_ram-1 ;last address ELSE ;SX52 MOV W,#mmc_data_ram+mmc_buffsize-1 ;last address ENDIF mov mmc_data_pointer,W ;data pointer for incoming data :mmc_read_byte call spix_get ;data read loop ;store incoming bytes into the data (circular) buffer INC mmc_data_pointer IF chip_type=0 ;SX18/28 MOV W,#buff_size*2+mmc_data_ram ;last address ELSE ;SX52 MOV W,#mmc_data_ram+mmc_buffsize ;last address ENDIF MOV W,mmc_data_pointer-W ;test for end of buffer MOV W,#mmc_data_ram ;pre-load new offset in case SNZ ;if not at end, skip ahead MOV mmc_data_pointer,W ;reset to start of buffer IF chip_type=0 MOV W,#$10 ;keep to odd banks for SX18/28 OR mmc_data_pointer,W ; " ENDIF :wait_buff_space MOV W,next_samp_ptr ;load output pointer MOV W,mmc_data_pointer-W ;and check if buffer full SNZ ;if not, skip ahead JMP :wait_buff_space ;wait till there's room mov mmc_temp_data,spix_data_io ;move data to global storage mov fsr,mmc_data_pointer ;use index register and W mov w,mmc_temp_data ;to move the date from SPIX temp data reg. mov ind,w ; to MMC data buffer BANK mmc_spix_ram ;reset to variables bank CLRB FSR.7 ; and make sure we're in lower 128reg. block djnz mmc_temp,:mmc_read_byte ;decrement byte counter djnz mmc_temp2,mmc_label43 ;decrement block counter call spix_get ;"read" two bytes CRC call spix_get ;the CRC is not implemented and thus the data are not used mmc_read_exit call spix_get ;DUMMY read cycle ; call spix_get ;DUMMY read cycle clrb mmc_read_write_data ;end the transfer and exit setb spix_cs_pin ;set MMC to inactive state jmp mmc_exit ;done ;******************* Send CMD24 ($58) (WRITE BLOCK) to MMC ********************* ;this is the first part of the BLOCK WRITE sequence - the command itself and the R1 ;response from the MMC mmc_cmd_block_write bank mmc_spix_ram ;select the RAM bank clr mmc_status ;clear the Status byte clrb spix_cs_pin ;set MMC_CS active (LOW) ;execute CMD16 :set_block_length mov mmc_temp,#$10 ;fixed delay call mmc_delay call spix_get ;"DUMMY" byte mov mmc_cmd,#$58 ;send the command call mmc_cmd_send call mmc_r1_get ;get the response call spix_get ;"DUMMY" byte test mmc_r1 ;if response was 00 then start jz mmc_write_data_block jmp mmc_write_exit ;end the transfer and exit ;*** WRITE CYCLE: Write the data block to MMC ;Send the Start Byte=$FE, wait for response (R1 type) ;Wait time= (mmc_write_wait_cycles * $FF). Total wait time should be =>1.5ms ; mmc_write_data_block call spix_get mov spix_data_io,#$fe ;send the start byte $FE call spix_send ;send the 512 data bytes the from the SX write data buffer. The buffer can be 16 or 32 bytes ;long. ;In a real wold when the buffer is empty, the program should wait untill the MAIN fills the buffer ;and returns to the black transfer again ;This program just sends the incrementing counter to the the MMC card ;It is intended to demonstrate the timing and the logic of the data transfer ;This part of the program heavily depends on the higher level program artichecture ; clr mmc_temp_data ;This is temp location for the Demo mov mmc_temp1,#mmc_blk_size/mmc_buffsize mmc_label38 mov mmc_temp,#mmc_buffsize ;set the byte counter and mov mmc_data_pointer,#mmc_data_ram ;data pointer for the data mmc_label39 ;this part of the program was tested and it works, but is not used for this demo ; mov fsr,mmc_data_pointer ;move the byte from MMC_DATA_RAM ; mov w,ind ;to MMC_SPIX_RAM using global ; mov mmc_temp_data,w ;location at $08 - MMC_TEMP_DATA ; bank mmc_spix_ram ; mov spix_data_io,mmc_temp_data ;this is just for the Demo - write incrementing values to MMC offset addresses bank mmc_spix_ram ;switch to spix control ram bank mov spix_data_io,mmc_temp_data ;Increment the counter and sent it to MMC card INC mmc_temp_data ;write increading values: DEMO only call spix_send ;send the byte inc mmc_data_pointer ;point to next data address or mmc_data_pointer,#$10 ;keep bank address in %xxx1000 range djnz mmc_temp,mmc_label39 ;decrement byte counter djnz mmc_temp1,mmc_label38 ;decrement SX RAM blocks counter call spix_get ;read the two byte "CRC" call spix_get ; " call mmc_r1_get ;get the response on the data block call spix_get ;the R1 in this case is not a typical one clrb mmc_error ;error detection in MMC_GET_R1 is not and mmc_r1,#$0f ;applicable cje mmc_r1,#$05,mmc_label37 jmp mmc_write_error ;error in the data - exit ;continue BLOCK WRITE dummy read cycles until MMC's BUSY signal is clear mmc_label37 setb mmc_busy ;set wait cycles counter mov mmc_temp1,#blk_wr_delay mmc_label36 mov mmc_temp,#$FF mmc_label35 call spix_get jb spix_in_pin,mmc_write_done ;wait for the BUSY signal to clear djnz mmc_temp,mmc_label35 djnz mmc_temp1,mmc_label36 jmp mmc_write_error ;error exit - time expired mmc_write_done clr mmc_status ;no-error exit jmp mmc_write_exit mmc_write_error setb mmc_error ;exit on error setb mmc_data_error mmc_write_exit call spix_get ;DUMMY read cycle clrb mmc_read_write_data setb spix_cs_pin jmp mmc_exit ;*** MMC Synchronization ;send $FF data to the MMC 10 times. Only called after power-up ; mmc_cmd_synchronize bank mmc_spix_ram ;select the RAM bank CALL spix_init ;initialize SPI I/O pins clr mmc_status ;initialize the MMC driver clr mmc_r1 clr mmc_r2 mov mmc_temp,#sync_duration ;get n bytes as a delay mmc_lable1 setb spix_out_pin ;in case of non-zero response from MMC call spix_get cjne spix_data_io,#$ff,mmc_lable2 djnz mmc_temp,mmc_lable1 mmc_lable2 mov mmc_r1,spix_data_io call spix_get ;DUMMY read cycle jmp mmc_exit ;*** MMC Initialization ;This function executes CMD0 and CMD1 with corresponding R1 MMC response detection ; mmc_cmd_initialize clrb spix_cs_pin ;set MCC_CS active (low) bank mmc_spix_ram ;init all the variables clr mmc_status ;clear the status byte CALL zero_MMC_addr ;set MMC data address to 0 mov mmc_cmd_crc,#$FF ;execute the CMDO command, exit if R1 is not equal to $01 mov mmc_temp,#$08 call mmc_delay ;execute 8 DUMMY cycles mov mmc_cmd,#$40 ;execute CMD0 call mmc_cmd_send call mmc_r1_get ;get a response byte back mov mmc_temp,#$10 call mmc_delay ;execute 16 DUMMY cycles cjne mmc_r1,#$01,mmc_label14 ;correct R1 is equal to #$01 ;The above code segment seems to go against MMC specs. The MMC isn't supposed to give ; a $00 response on this command but it seems to if we try to repeat it. ;The correct (from the manual point of view) sequence should look like following, ; (but it does not work): ; cje mmc_r1,#$01,mmc_label15 ;correct R1 is equal to #$01 ; setb mmc_error ;if not - set the error flag ; jmp mmc_label14 ;and exit ;execute the CMD1 command until R1==00 or MMC_CMD1_WAIT times mmc_label15 mov mmc_temp2,#cmd1_resp_wait ;load wait duration for response mmc_label13 clr mmc_status ;reset error status mov mmc_temp,#cmd1_delay1 ;send n (=8?) DUMMY bytes call mmc_delay mov mmc_cmd,#$41 ;send CMD1 code call mmc_cmd_send call mmc_r1_get ;get the response mov mmc_temp,#cmd1_delay2 ;load delay call mmc_delay ;send n (=16?) DUMMY bytes MOV W,#cmd1_delay3 ;load delay value call mmc_wait ;wait for some time test mmc_r1 ;check for response jz mmc_label14 ;correct R1 is equal to #$00 djnz mmc_temp2,mmc_label13 ;if not - repeat mmc_cmd1_wait times mmc_label14 setb spix_cs_pin ;set MMC_CS to inactive (HIGH) jmp mmc_exit ;exit ;=========================================================================== ; ;*************************** Main Program Code ***************************** ; ;******** ;* Main * ;******** ; ; ORG 100h ; Reset_entry IF chip_type=1 ;SX52 MOV FSR,#$0A ;load first offset ELSE ;SX52 CLR FSR ;point to beginning of RAM ENDIF :zero_ram IF chip_type=0 SB FSR.4 ;are we on low half of bank? SETB FSR.3 ;If so, don't touch regs 0-7 ENDIF CLR IND ;clear using indirect addressing IJNZ FSR,:zero_ram ;repeat until done :setup_regs MOV RA,#RA_init ;initialize port RA MOV !RA,#RA_IO ;Set RA in/out directions MOV RB,#RB_init ;initialize port RB MOV !RB,#RB_io ;Set RB in/out directions MOV RC,#RC_init ;initialize port RC MOV !RC,#RC_io ;Set RC in/out directions MOV !OPTION,#option_init ;initialize OPTION reg. :initialize BANK analog ;switch to adc/pwm/timer bank MOV W,#pwm0_init ;get initial pwm0 voltage MOV pwm0,W ; and store it MOV W,#pwm1_init ;get initial pwm0 voltage MOV pwm1,W ; and store it MOV W,#samp_freq&$FF ;keep low byte of sample rate MOV freq_low,W ;store it MOV W,#samp_freq>>8 ;keep high byte of sample rate MOV freq_high,W ;store it IF chip_type=0 ;SX18/28 MOV W,#buff_size*2+mmc_data_ram-2 ;last address (-2 to keep stereo syncing) ELSE ;SX52 MOV W,#mmc_data_ram+mmc_buffsize-2 ;last address (-2 to keep stereo syncing) ENDIF MOV next_samp_ptr,W ;set sample pointer to start CALL spix_init ;SPIX port pin default states CALL zero_MMC_addr ;reset MMC data address pointers ; ;************** Main program loop Mainloop :sync bank mmc_spix_ram mov mmc_cmd,#$ff ;execute the SYNCHRONIZE function call mmc_execute :init mov mmc_cmd,#$fe ;execute the INITIALIZE function call mmc_execute test mmc_status jnz :sync ;repeat in case of syncronization/initialization error :write mov mmc_cmd,#$FA ;execute the 512 byte block write command ; call mmc_execute ;uncomment this to write the block test mmc_status ;check how write procedure went sz JMP :error ;exit if we got an error writing data block :read_init CALL zero_MMC_addr ;reset MMC data address pointer => 0 :read_loop mov mmc_cmd,#$FD ;execute the block read command call mmc_execute test mmc_status ;check how read procedure went SZ ; JMP :error ;exit if we got an error reading data block INC mmc_addr_b1 ;count through multiple blocks INCSZ mmc_addr_b1 ; (b1=b1+2 => advance 512 bytes at a time) JMP :read_loop ;keep reading IF MMC_size<16 INC mmc_addr_b2 ;continue through multiple blocks MOV W,#end_of_mem ;load end of storage memory (or sample size) MOV W,mmc_addr_b2-W ; and see if we're there yet ELSE ; for MMC cards >16Meg INCSZ mmc_addr_b2 ;continue through multiple blocks JMP :read_loop ;keep reading INC mmc_addr_b3 ;continue through multiple blocks MOV W,#end_of_mem ;load end of storage memory (or sample size) MOV W,mmc_addr_b3-W ; and see if we're there yet ENDIF SZ ;if so, skip ahead JMP :read_loop ;otherwise, keep looping :done_read JMP :read_init ;run through the whole read again :error JMP MainLoop ;in case of read/write error, re-synchronize ; ;*********************************************** END
| file: /Techref/SCENIX/contest/mmc/sx52mmc.src, 38KB, , updated: 2000/11/10 15:24, local time: 2024/11/12 11:45,
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