/* USB led driver firmware Copyright 2008 Jacob Joseph This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ /* Communications code between an FTDI 245R USB fifo chip, and three TI5940 pwm led drivers. For use on a PIC16887, on the USB LED driver board for driving five 350mA Lamina RGB lights. Note that each TI5940 port can attain a maximum of 120mA, so three are grouped for each color channel. This is easier than proper constant-current amplification. Functional Overview: ----------------------------------- A tight loop in main monitors the 245R RD line, indicating new input data. The first byte defined a command, followed by a variable-length set of parameters, which are clocked in immediately. Global state bits are then (atomically) set if, for example, a color update should be performed. The TI5940 clocking is performed first by the clkout pin, at OSO/4. Blanking, and all communications with the TI5940 chips must be coordinated such that commands complete before a blank cycle. These are handled by an interrupt driven by Timer 1. Note that commands are processed only at the next interrupt cycle, introducing some latency. To Do: Ignore incomplete commands. CRC on received data? Just echo commands or checksum back to pc? Could an interrupt be used for watching RD?) Use UART for debug output, in ASCII USB command set: ----------------------------------- 0x00 : grayscale data. 5ports x 3colors x 2bytes(12 bit resolution) to follow, in order of port,{r,g,b},{high,low}(12bit x 5port x 3color) to follow 0x01 : dot correction data. 5ports x 3colors x 1byte(6 bit resolution) to follow. 0x02 : blank immediately, disable blank interrupt 0x03 : resume blank interrupt, unblanking at next timer event 0x80 : reset command input. Next byte should be a command 0x81 : disable GIE 0x82 : enable GIE 0xF0 : debug: echo received bytes, perform nothing (0x80 breaks) 0xF1 : debug: set color change bit, to refresh grayscale 0xF2 : debug: set dot change bit, to refresh dot correction 0xF3 : debug: echo color table 0xF4 : debug: echo dot correction table 0xF5 : debug: echo state bits Port Assignments: ------------------------------------ 16F887 FTDI245RL: RD0 TxE RD1 RxF RD2 RD RD3 WR RB0..7 D0..7 TI communication RA6 (clkout) TI gsclk RC0 (T1OSO) TI xlat (should T1OSO be used on blank?) RC1 TI blank RC3 (sclk) TI sclk RC4 (sin) TI#2 sout RC5 (sout) TI#0 sin RE1 TI dcprg (keep high) RE2 TI vprg ICSP RB3 (PGM) RB6 (ICSPCLK) RB7 (ICSPDAT) RE3 (MCLR/Vpp) UART RC6 (tx) RC7 (rx) LED TI5940 ports ------------------------------------ led0_r TI0 OUT0 TI0 OUT1 TI0 OUT2 led0_g TI0 OUT3 TI0 OUT4 TI0 OUT5 led0_b TI0 OUT6 TI0 OUT7 TI0 OUT8 led1_r TI0 OUT9 TI0 OUT10 TI0 OUT11 led1_g TI0 OUT12 TI0 OUT13 TI0 OUT14 led1_b TI0 OUT15 TI1 OUT0 TI1 OUT1 led2_r TI1 OUT2 TI1 OUT3 TI1 OUT4 led2_g TI1 OUT5 TI1 OUT6 TI1 OUT7 led2_b TI1 OUT8 TI1 OUT9 TI1 OUT10 led3_r TI1 OUT11 TI1 OUT12 TI1 OUT13 led3_g TI1 OUT14 TI1 OUT15 TI2 OUT0 led3_b TI2 OUT1 TI2 OUT1 TI2 OUT2 led4_r TI2 OUT3 TI2 OUT4 TI2 OUT5 led4_g TI2 OUT6 TI2 OUT7 TI2 OUT8 led4_b TI2 OUT9 TI2 OUT10 TI2 OUT11 sdcc --debug -mpic14 -p16f887 main.c */ #define __16f887 /*#define NO_BIT_DEFINES*/ #include "pic/pic16f887.h" #include "main.h" #define NPORTS 5 unsigned char raw_frame[72]; unsigned char raw_dot[12]; struct led colors[NPORTS]; unsigned char do_color_update; unsigned char do_dot_update; void Intr(void) __interrupt 0 { /* Timer 0 expired. Pulse blank */ if (TMR0IF) { TI_BLANK = 1; TMR0 = 0; TI_BLANK = 0; TMR0IF = 0; } } void init_pic() { INTCON = 0; TMR0 = 0; T0IE = 1; /* enable Timer 0 overflow interrupt */ CCP1CON = 0; /* disable CCP */ CCP2CON = 0; /*SSPCON = 0b00100000;*/ /* enable hardware SPI */ /*SSPCON = 0x20;*/ /* enable hardware SPI */ SSPCON = 0; PIE1 = 0; /* disable peripheral interrupts */ PIE2 = 0; CM1CON0 = 0; /* disable comparitors */ CM2CON0 = 0; /*OSCCON = 0b01111000;*/ /* 8mhz */ /*OSCCON = 0b00001000; */ /* 31.25khz */ OSCCON = 0x78; /* 8mhz */ /*OSCCON = 0x08;*/ /* 31.25khz */ /* Timer 0 configuration for TI_BLANK 1:16 prescaler (1 click every 16 cycles, overflow every 4096) */ /*OPTION_REG = 0b00000011; */ OPTION_REG = 0x03; /* Port configuration */ PORTA = 0; PORTB = 0; PORTC = 0; PORTD = 0; PORTE = 0; /* Start with USB_RD, TI_BLANK high */ FT_RD = 1; FT_WR = 1; TI_DCPRG = 1; TI_VPRG = 1; TI_BLANK = 1; TI_XLAT = 0; TI_SCLK = 0; ANSEL = 0; /* digital I/O */ TRISA = 0x00; /* unused, save RA6 */ ANSELH = 0; /* digital I/O */ /*WPUB weak pull-up */ TRISB = 0xFF; /* USB data input */ TRISC = 0x10; /* in: 4 out: 0,1,3,5 */ TRISD = 0xC3; /* in: 0,1,6,7 out: 2,3 */ /* note RE3 (mclr) is input only */ TRISE = 0x00; /* out: 1,2 */ do_color_update = 0; do_dot_update = 0; /*RD4 = 1; */ } unsigned char usb_read_byte( void) { unsigned char cmd; RD4 = 1; /* wait for RxF to be low */ while (FT_RXF) {}; RD4 = 0; FT_RD = 0; cmd = FT_BYTE; /* hack to use RD6,7 instead of RB6,7 (which are ICD) */ /* ICD hack if (RD6) cmd |= 0x40; else cmd &= ~0x40; if (RD7) cmd |= 0x80; else cmd &= ~0x80; */ FT_RD = 1; return cmd; } void usb_write_byte( unsigned char c) { TRISB = 0x00; TRISD &= 0x3F; FT_BYTE = c; /* ICD hack if (c & 0x40) RD6 = 1; else RD6 = 0; if (c & 0x80) RD7 = 1; else RD7 = 0; */ while (1) { /* Wait for txe to be low before writing */ if (!FT_TXE) break; } FT_WR = 0; FT_WR = 1; TRISB = 0xFF; TRISD |= 0xC0; } /* call when ready to read the FTDI chip */ void usb_read( void) { unsigned char cmd; unsigned char i; cmd = usb_read_byte(); switch(cmd) { case(0x00): /* grayscale data: 30 bytes, ordered port,{r,g,b},{h,l} */ /*for (i=0; i < NPORTS; i++) { colors[i].r = usb_read_byte() << 8; colors[i].r |= usb_read_byte(); colors[i].g = usb_read_byte() << 8; colors[i].g |= usb_read_byte(); colors[i].b = usb_read_byte() << 8; colors[i].b |= usb_read_byte(); }*/ do_color_update = 1; break; case(0x01): /* dot correction data 15 bytes, ordered port,{r,g,b} */ /*for (i=0; i < NPORTS; i++) { colors[i].rdot = usb_read_byte(); colors[i].gdot = usb_read_byte(); colors[i].bdot = usb_read_byte(); }*/ do_dot_update = 1; break; case(0x02): /* raw grayscale data, chip 0. 16x12bits = 24 bytes ordered msb first */ for (i=0; i < 72; i++) { raw_frame[i] = usb_read_byte(); } do_color_update = 1; break; case(0x03): /* raw dot correction data, chip 0. 16x6bits = 12 bytes ordered msb first */ for (i=0; i < 12; i++) { raw_dot[i] = usb_read_byte(); } do_dot_update = 1; break; case(0x80): /* reset command input. */ xD5; break; case(0x81): /* disable GIE */ GIE = 0; break; case(0x82): /* enable GIE */ GIE = 1; break; case(0xF3): /* echo color table */ for (i=0; i < NPORTS; i++) { usb_write_byte( (unsigned char) (colors[i].r >> 8)); usb_write_byte( (unsigned char) colors[i].r & 0xFF); usb_write_byte( (unsigned char) (colors[i].g >> 8)); usb_write_byte( (unsigned char) colors[i].g & 0xFF); usb_write_byte( (unsigned char) (colors[i].b >> 8)); usb_write_byte( (unsigned char) colors[i].b & 0xFF); } break; case(0xF4): /* echo dot table */ for (i=0; i < NPORTS; i++) { usb_write_byte( colors[i].rdot); usb_write_byte( colors[i].gdot); usb_write_byte( colors[i].bdot); } break; case(0xF5): /* echo state bits */ usb_write_byte( do_color_update); usb_write_byte( do_dot_update); break; } } void spi_send_byte( unsigned char b) { unsigned char i; for( i=0; i < 8; i++) { if( b & 0x80) TI_SIN = 1; else TI_SIN = 0; TI_SCLK = 1; b <<= 1; TI_SCLK = 0; } /* bit_count = 8; _asm Transmit_bit$: btfsc _b, 7 goto Transmit_hi bcf _PORTC_bits, 5 goto Transmit_clkout Transmit_hi bsf _PORTC_bits, 5 Transmit_clkout bsf _PORTC_bits, 3 rlf _b, F bcf _PORTC_bits, 3 decfsz _bit_count, F goto Transmit_bit _endasm; */ } void ti_send_frame(void) { unsigned char i; unsigned char first_cycle; /* wait for timer0 to reset, allowing enough time to complete transmission before another reset */ while (TMR0 > 10) {}; if (TI_VPRG) { TI_VPRG = 0; first_cycle = 1; } else first_cycle = 0; for( i=0; i < 72; i++) { /*SSPBUF = raw_frame[i];*/ /* wait for byte to be clocked out */ /*while (BF) {};*/ spi_send_byte( raw_frame[i]); } /* pulse xlat */ TI_XLAT = 1; TI_XLAT = 0; if (first_cycle) { TI_SCLK = 1; TI_SCLK = 0; first_cycle = 0; } do_color_update = 0; } void ti_send_dot(void) { unsigned char i; while (TMR0 > 10) {}; TI_VPRG = 1; TI_XLAT = 0; for( i=0; i < 12; i++) { /*SSPBUF = raw_dot[i]; */ /* wait for byte to be clocked out */ /*while (BF) {}; */ spi_send_byte( raw_dot[i]); } TI_XLAT = 1; TI_XLAT = 0; do_dot_update = 0; } void main(void) { unsigned char i; init_pic(); GIE = 1; /* start interrupts */ for( i=0; i < 12; i++) { raw_dot[i] = 0xFF; } ti_send_dot(); for (i = 0; i < 24; i++) { raw_frame[i] = 0xFF; } /*for (i = 23; i > 10; i--) { raw_frame[i] = 0x00; }*/ ti_send_frame(); while (1) { /* When low, data available */ if (!FT_RXF) { usb_read(); } if (do_color_update) ti_send_frame(); if (do_dot_update) ti_send_dot(); } }