| 1 | /* bitbang_cbus.c |
| 2 | |
| 3 | Example to use CBUS bitbang mode of newer chipsets. |
| 4 | You must enable CBUS bitbang mode in the EEPROM first. |
| 5 | |
| 6 | Thanks to Steve Brown <sbrown@ewol.com> for the |
| 7 | the information how to do it. |
| 8 | |
| 9 | The top nibble controls input/output and the bottom nibble |
| 10 | controls the state of the lines set to output. The datasheet isn't clear |
| 11 | what happens if you set a bit in the output register when that line is |
| 12 | conditioned for input. This is described in more detail |
| 13 | in the FT232R bitbang app note. |
| 14 | |
| 15 | BITMASK |
| 16 | CBUS Bits |
| 17 | 3210 3210 |
| 18 | xxxx xxxx |
| 19 | | |------ Output Control 0->LO, 1->HI |
| 20 | |----------- Input/Output 0->Input, 1->Output |
| 21 | |
| 22 | Example: |
| 23 | All pins to output with 0 bit high: 0xF1 (11110001) |
| 24 | Bits 0 and 1 to input, 2 and 3 to output and masked high: 0xCC (11001100) |
| 25 | |
| 26 | This program is distributed under the GPL, version 2 |
| 27 | */ |
| 28 | |
| 29 | #include <stdio.h> |
| 30 | #include <unistd.h> |
| 31 | #include <ftdi.h> |
| 32 | |
| 33 | int main(int argc, char **argv) |
| 34 | { |
| 35 | struct ftdi_context ftdic; |
| 36 | int f,i; |
| 37 | char buf[1]; |
| 38 | unsigned char bitmask; |
| 39 | |
| 40 | ftdi_init(&ftdic); |
| 41 | |
| 42 | f = ftdi_usb_open(&ftdic, 0x0403, 0x6001); |
| 43 | if(f < 0 && f != -5) { |
| 44 | fprintf(stderr, "unable to open ftdi device: %d (%s)\n", f, ftdi_get_error_string(&ftdic)); |
| 45 | exit(-1); |
| 46 | } |
| 47 | printf("ftdi open succeeded: %d\n",f); |
| 48 | |
| 49 | // enable CBUS |
| 50 | bitmask = 0x71; |
| 51 | printf("enabling CBUS mode\n"); |
| 52 | f = ftdi_set_bitmode(&ftdic, bitmask, 0x20); // cbus[0] as input (high), cbus[1-3] as output |
| 53 | if (f < 0) { |
| 54 | fprintf(stderr, "set_bitmode failed for 0x%x, error %d (%s)\n", bitmask, f, ftdi_get_error_string(&ftdic)); |
| 55 | exit(-1); |
| 56 | } |
| 57 | |
| 58 | // write to CBUS |
| 59 | buf[0] = 0xFF; |
| 60 | f = ftdi_write_data(&ftdic, buf, 1); |
| 61 | if(f < 0) { |
| 62 | fprintf(stderr,"write failed for 0x%x, error %d (%s)\n", buf[0], f, ftdi_get_error_string(&ftdic)); |
| 63 | exit(-1); |
| 64 | } |
| 65 | |
| 66 | // read CBUS |
| 67 | f = ftdi_read_pins(&ftdic, &buf[0]); |
| 68 | if (f < 0) { |
| 69 | fprintf(stderr, "read_pins failed, error %d (%s)\n", f, ftdi_get_error_string(&ftdic)); |
| 70 | exit(-1); |
| 71 | } |
| 72 | |
| 73 | printf("disabling bitbang mode\n"); |
| 74 | ftdi_disable_bitbang(&ftdic); |
| 75 | |
| 76 | ftdi_usb_close(&ftdic); |
| 77 | ftdi_deinit(&ftdic); |
| 78 | } |