--- /dev/null
+/* bitbang_cbus.c
+
+ Example to use CBUS bitbang mode of newer chipsets.
+ You must enable CBUS bitbang mode in the EEPROM first.
+
+ Thanks to Steve Brown <sbrown@ewol.com> for the
+ the information how to do it.
+
+ The top nibble controls input/output and the bottom nibble
+ controls the state of the lines set to output. The datasheet isn't clear
+ what happens if you set a bit in the output register when that line is
+ conditioned for input. This is described in more detail
+ in the FT232R bitbang app note.
+
+ BITMASK
+ CBUS Bits
+ 3210 3210
+ xxxx xxxx
+ | |------ Output Control 0->LO, 1->HI
+ |----------- Input/Output 0->Input, 1->Output
+
+ Example:
+ All pins to output with 0 bit high: 0xF1 (11110001)
+ Bits 0 and 1 to input, 2 and 3 to output and masked high: 0xCC (11001100)
+
+ This program is distributed under the GPL, version 2
+*/
+
+#include <stdio.h>
+#include <unistd.h>
+#include <ftdi.h>
+
+int main(int argc, char **argv)
+{
+ struct ftdi_context ftdic;
+ int f,i;
+ char buf[1];
+ unsigned char bitmask;
+
+ ftdi_init(&ftdic);
+
+ f = ftdi_usb_open(&ftdic, 0x0403, 0x6001);
+ if(f < 0 && f != -5) {
+ fprintf(stderr, "unable to open ftdi device: %d (%s)\n", f, ftdi_get_error_string(&ftdic));
+ exit(-1);
+ }
+ printf("ftdi open succeeded: %d\n",f);
+
+ // enable CBUS
+ bitmask = 0x71;
+ printf("enabling CBUS mode\n");
+ f = ftdi_set_bitmode(&ftdic, bitmask, 0x20); // cbus[0] as input (high), cbus[1-3] as output
+ if (f < 0) {
+ fprintf(stderr, "set_bitmode failed for 0x%x, error %d (%s)\n", bitmask, f, ftdi_get_error_string(&ftdic));
+ exit(-1);
+ }
+
+ // write to CBUS
+ buf[0] = 0xFF;
+ f = ftdi_write_data(&ftdic, buf, 1);
+ if(f < 0) {
+ fprintf(stderr,"write failed for 0x%x, error %d (%s)\n", buf[0], f, ftdi_get_error_string(&ftdic));
+ exit(-1);
+ }
+
+ // read CBUS
+ f = ftdi_read_pins(&ftdic, &buf[0]);
+ if (f < 0) {
+ fprintf(stderr, "read_pins failed, error %d (%s)\n", f, ftdi_get_error_string(&ftdic));
+ exit(-1);
+ }
+
+ printf("disabling bitbang mode\n");
+ ftdi_disable_bitbang(&ftdic);
+
+ ftdi_usb_close(&ftdic);
+ ftdi_deinit(&ftdic);
+}