''********************************************* ''* Bidirectional Packet Driver * ''* (C) 2011-2015 David Betz * ''* Based on: * ''* Full-Duplex Serial Driver v1.1 Extended * ''* (C) 2006 Parallax, Inc. * ''********************************************* CON ' command codes #0 CMD_IDLE ' must be zero CMD_RXPACKET CMD_TXPACKET ' status codes #0 STATUS_OK STATUS_ERROR ' init offsets #0 INIT_MBOX ' zeroed by driver after init is done INIT_RXPIN INIT_TXPIN INIT_BAUDRATE _INIT_SIZE ' mailbox offsets #0 MBOX_CMD MBOX_TYPE ' or pointer to type on rx MBOX_BUFFER MBOX_LENGTH ' or pointer to length on rx MBOX_STATUS MBOX_COG ' not really part of the mailbox _MBOX_SIZE ' character codes SOH = $01 ' start of a packet VAR long mbox[_MBOX_SIZE] PUB start(rxpin, txpin, baudrate) | init[_INIT_SIZE], cogn '' Start packet driver - starts a cog '' returns zero on success and non-zero if no cog is available '' ' stop the driver if it's already running stop ' start the driver cog init[INIT_MBOX] := @mbox init[INIT_RXPIN] := rxpin init[INIT_TXPIN] := txpin init[INIT_BAUDRATE] := clkfreq / baudrate cogn := mbox[MBOX_COG] := cognew(@entry, @init) + 1 ' if the cog started okay wait for it to finish initializing if cogn repeat while init[INIT_MBOX] <> 0 return !cogn PUB stop if mbox[MBOX_COG] cogstop(mbox[MBOX_COG]~ - 1) PUB rx(ptype, buffer, plength) mbox[MBOX_BUFFER] := buffer mbox[MBOX_LENGTH] := long[plength] mbox[MBOX_CMD] := CMD_RXPACKET repeat while mbox[MBOX_CMD] <> CMD_IDLE long[ptype] := mbox[MBOX_TYPE] long[plength] := mbox[MBOX_LENGTH] return mbox[MBOX_STATUS] PUB tx(type, buffer, length) mbox[MBOX_TYPE] := type mbox[MBOX_BUFFER] := buffer mbox[MBOX_LENGTH] := length mbox[MBOX_CMD] := CMD_TXPACKET repeat while mbox[MBOX_CMD] <> CMD_IDLE return mbox[MBOX_STATUS] DAT '*********************************** '* Assembly language serial driver * '*********************************** org ' ' ' Entry ' entry mov t1, par 'get init structure address rdlong t2, t1 'get the mailbox address mov cmd_ptr, t2 'offset 0 - cmd add t2, #4 mov pkt_type_ptr, t2 'offset 1 - type add t2, #4 mov pkt_buffer_ptr, t2 'offset 2 - buffer add t2, #4 mov pkt_length_ptr, t2 'offset 3 - length add t2, #4 mov pkt_status_ptr, t2 'offset 4 - status add t1, #4 'get rx_pin rdlong t2, t1 mov rxmask, #1 shl rxmask, t2 add t1, #4 'get tx_pin rdlong t2, t1 mov txmask, #1 shl txmask, t2 add t1, #4 'get bit_ticks rdlong bitticks, t1 or outa, txmask 'initialize the tx pin or dira, txmask andn dira, rxmask 'initialize the rx pin rdlong t1, #0 add t1, cnt waitcnt t1, #0 mov t1, #CMD_IDLE 'no command in progress wrlong t1, cmd_ptr mov t1, #0 'signal end of initialization wrlong t1, par next_cmd mov t1, #CMD_IDLE 'no command in progress wrlong t1, cmd_ptr :wait rdlong t1, cmd_ptr wz 'wait for a command if_z jmp #:wait add t1, #dispatch jmp t1 dispatch jmp #next_cmd 'should never happen jmp #do_rxpacket jmp #do_txpacket ' receive a packet do_rxpacket rdlong rcv_ptr, pkt_buffer_ptr rdlong t1, pkt_length_ptr rdlong rcv_max, t1 call #rxpacket if_c wrlong ok_status, pkt_status_ptr if_c wrlong rcv_type, pkt_type_ptr if_c wrlong rcv_length, pkt_length_ptr if_nc wrlong error_status, pkt_status_ptr jmp #next_cmd ' send a packet do_txpacket rdlong xmt_type, pkt_type_ptr rdlong xmt_ptr, pkt_buffer_ptr rdlong xmt_length, pkt_length_ptr call #txpacket if_c wrlong ok_status, pkt_status_ptr if_nc wrlong error_status, pkt_status_ptr jmp #next_cmd ok_status long STATUS_OK error_status long STATUS_ERROR ' receive a packet ' input: ' rcv_ptr points to the receive buffer ' rcv_max is the maximum number of bytes to receive ' output: ' rcv_type is the packet type ' rcv_length is the length of the packet received ' C is set on return if the packet was received successfully ' C is clear on return if there was an error rxpacket call #rxbyte cmp rxdata, #SOH wz if_nz jmp #rxpacket call #rxbyte ' receive packet type mov rcv_type, rxdata mov rcv_chk, rxdata call #rxbyte ' receive hi byte of packet length mov rcv_length, rxdata shl rcv_length, #8 add rcv_chk, rxdata call #rxbyte ' receive lo byte of packet length or rcv_length, rxdata add rcv_chk, rxdata call #rxbyte ' receive header checksum and rcv_chk, #$ff cmp rxdata, rcv_chk wz if_nz jmp #rxerror cmp rcv_length, rcv_max wz, wc if_a jmp #rxerror mov crc, #0 mov rcv_cnt, rcv_length wz if_z jmp #:crc :next call #rxbyte ' receive the next data byte mov crcdata, rxdata call #updcrc ' update the crc wrbyte rxdata, rcv_ptr add rcv_ptr, #1 djnz rcv_cnt, #:next :crc call #rxbyte mov crcdata, rxdata call #updcrc ' update the crc call #rxbyte mov crcdata, rxdata call #updcrc ' update the crc cmp crc, #0 wz ' check the crc if_nz jmp #rxerror test $, #1 wc ' set c to indicate success rxpacket_ret ret rxerror test $, #0 wc ' clear c to indicate failure jmp rxpacket_ret ' transmit a packet ' input: ' xmt_type is the packet type ' xmt_ptr points to the packet data ' xmt_length is the number of bytes of data ' output: ' C is set on return if the packet was received successfully ' C is clear on return if there was an error txpacket mov txdata, #SOH call #txbyte mov txdata, xmt_type mov xmt_chk, txdata call #txbyte mov txdata, xmt_length shr txdata, #8 add xmt_chk, txdata call #txbyte mov txdata, xmt_length and txdata, #$ff add xmt_chk, txdata call #txbyte mov txdata, xmt_chk and txdata, #$ff call #txbyte mov crc, #0 mov xmt_cnt, xmt_length wz if_z jmp #:crc :next rdbyte txdata, xmt_ptr add xmt_ptr, #1 mov crcdata, txdata call #updcrc call #txbyte djnz xmt_cnt, #:next :crc mov crcdata, #0 call #updcrc call #updcrc mov txdata, crc shr txdata, #8 call #txbyte mov txdata, crc and txdata, #$ff call #txbyte test $, #1 wc ' set c to indicate success txpacket_ret ret ' receive a byte ' output: ' rxdata is the byte received rxbyte waitpne rxmask, rxmask ' wait for a start bit mov rxcnt, bitticks ' wait until half way through the bit time shr rxcnt, #1 add rxcnt, bitticks add rxcnt, cnt mov rxbits, #9 ' receive 8 data bits and the stop bit :next waitcnt rxcnt, bitticks ' wait until the center of the next bit test rxmask, ina wc ' sample the rx pin rcr rxdata, #1 ' add to the byte being received djnz rxbits, #:next shr rxdata, #32-9 ' shift the received data to the low bits and rxdata, #$ff ' mask off the stop bit waitpeq rxmask, rxmask ' wait for the end of the stop bit rxbyte_ret ret ' transmit a byte ' input: ' txdata is the byte to send (destroyed on return) txbyte or txdata, #$100 ' or in a stop bit shl txdata, #1 ' shift in a start bit mov txcnt, cnt add txcnt, bitticks mov txbits, #10 :next shr txdata, #1 wc muxc outa, txmask waitcnt txcnt, bitticks djnz txbits, #:next waitcnt txcnt, bitticks txbyte_ret ret bitticks long 0 rxmask long 0 rxdata long 0 rxbits long 0 rxcnt long 0 txmask long 0 txdata long 0 txbits long 0 txcnt long 0 ' update the crc ' input: ' crc the current crc ' crcdata the data to add to the crc ' output: ' crc the updated crc updcrc mov t1, crc test t1, #$100 wz shr t1, #9 add t1, #crctab movs :load, t1 shl crc, #8 :load mov t1, 0-0 if_nz shr t1, #16 xor crc, t1 xor crc, crcdata and crc, word_mask updcrc_ret ret crc long 0 crcdata long 0 ' ' ' Initialized data ' ' zero long 0 word_mask long $ffff crctab word $0000, $1021, $2042, $3063, $4084, $50a5, $60c6, $70e7 word $8108, $9129, $a14a, $b16b, $c18c, $d1ad, $e1ce, $f1ef word $1231, $0210, $3273, $2252, $52b5, $4294, $72f7, $62d6 word $9339, $8318, $b37b, $a35a, $d3bd, $c39c, $f3ff, $e3de word $2462, $3443, $0420, $1401, $64e6, $74c7, $44a4, $5485 word $a56a, $b54b, $8528, $9509, $e5ee, $f5cf, $c5ac, $d58d word $3653, $2672, $1611, $0630, $76d7, $66f6, $5695, $46b4 word $b75b, $a77a, $9719, $8738, $f7df, $e7fe, $d79d, $c7bc word $48c4, $58e5, $6886, $78a7, $0840, $1861, $2802, $3823 word $c9cc, $d9ed, $e98e, $f9af, $8948, $9969, $a90a, $b92b word $5af5, $4ad4, $7ab7, $6a96, $1a71, $0a50, $3a33, $2a12 word $dbfd, $cbdc, $fbbf, $eb9e, $9b79, $8b58, $bb3b, $ab1a word $6ca6, $7c87, $4ce4, $5cc5, $2c22, $3c03, $0c60, $1c41 word $edae, $fd8f, $cdec, $ddcd, $ad2a, $bd0b, $8d68, $9d49 word $7e97, $6eb6, $5ed5, $4ef4, $3e13, $2e32, $1e51, $0e70 word $ff9f, $efbe, $dfdd, $cffc, $bf1b, $af3a, $9f59, $8f78 word $9188, $81a9, $b1ca, $a1eb, $d10c, $c12d, $f14e, $e16f word $1080, $00a1, $30c2, $20e3, $5004, $4025, $7046, $6067 word $83b9, $9398, $a3fb, $b3da, $c33d, $d31c, $e37f, $f35e word $02b1, $1290, $22f3, $32d2, $4235, $5214, $6277, $7256 word $b5ea, $a5cb, $95a8, $8589, $f56e, $e54f, $d52c, $c50d word $34e2, $24c3, $14a0, $0481, $7466, $6447, $5424, $4405 word $a7db, $b7fa, $8799, $97b8, $e75f, $f77e, $c71d, $d73c word $26d3, $36f2, $0691, $16b0, $6657, $7676, $4615, $5634 word $d94c, $c96d, $f90e, $e92f, $99c8, $89e9, $b98a, $a9ab word $5844, $4865, $7806, $6827, $18c0, $08e1, $3882, $28a3 word $cb7d, $db5c, $eb3f, $fb1e, $8bf9, $9bd8, $abbb, $bb9a word $4a75, $5a54, $6a37, $7a16, $0af1, $1ad0, $2ab3, $3a92 word $fd2e, $ed0f, $dd6c, $cd4d, $bdaa, $ad8b, $9de8, $8dc9 word $7c26, $6c07, $5c64, $4c45, $3ca2, $2c83, $1ce0, $0cc1 word $ef1f, $ff3e, $cf5d, $df7c, $af9b, $bfba, $8fd9, $9ff8 word $6e17, $7e36, $4e55, $5e74, $2e93, $3eb2, $0ed1, $1ef0 ' ' Uninitialized data ' t1 res 1 t2 res 1 xmt_type res 1 xmt_length res 1 xmt_chk res 1 xmt_ptr res 1 xmt_cnt res 1 rcv_type res 1 rcv_length res 1 'packet length rcv_chk res 1 'header checksum rcv_max res 1 'maximum packet data length rcv_ptr res 1 'data buffer pointer rcv_cnt res 1 'data buffer count cmd_ptr res 1 pkt_type_ptr res 1 pkt_buffer_ptr res 1 pkt_length_ptr res 1 pkt_status_ptr res 1 fit 496