When working with some flash chips using the Bus Pirate programmer, the use of the Bus Pirate's on-board pull-up resistors is sometimes necessary.
Use of said pull-up resistors requires the user to apply a voltage to the VPU pin of the Bus Pirate, and then command it to use them. Included is a patch to initialize the Bus Pirate's pull-up resistors with a 'pullups=1' at the command line: e.g. flashrom -p buspirate_spi:dev=/dev/buspirate,pullups=1 Here is a link to information pertaining to what this patch does. http://dangerousprototypes.com/docs/SPI_(binary)#0100wxyz_-_Configure_peripherals_w.3Dpower.2C_x.3Dpull-ups.2C_y.3DAUX.2C_z.3DCS Currently, flashrom sends 0x4b, which does not set the "pull-ups" bit high. Optionally sending 0x4f instead will enable them. --- trunk/buspirate_spi.c 2013-01-01 04:03:42.507602657 -0500 +++ src/flashrom/buspirate_spi.c 2013-01-01 04:02:25.847578106 -0500 @@ -204,11 +204,13 @@ char *dev = NULL; char *speed = NULL; char *tmp; + char *pullups = NULL; unsigned int fw_version_major = 0; unsigned int fw_version_minor = 0; int spispeed = 0x7; int ret = 0; int i; + int ipullup = 0; dev = extract_programmer_param("dev"); if (dev && !strlen(dev)) { @@ -220,6 +222,16 @@ return 1; } + /* enable pull-up resistors? */ + pullups = extract_programmer_param("pullups"); + if(pullups) { + ipullup = atoi(pullups); + + if(ipullup == 1) { + msg_pinfo("Enabled Bus Pirate pull-up resistors.\n"); + } + } + speed = extract_programmer_param("spispeed"); if (speed) { for (i = 0; spispeeds[i].name; i++) @@ -395,7 +407,7 @@ } /* Initial setup (SPI peripherals config): Enable power, CS high, AUX */ - bp_commbuf[0] = 0x40 | 0xb; + bp_commbuf[0] = 0x40 | ((ipullup == 1) ? 0xf : 0xb); ret = buspirate_sendrecv(bp_commbuf, 1, 1); if (ret) return 1; Happy New Year! Signed-off-by: Brian Salcedo <[email protected]> _______________________________________________ flashrom mailing list [email protected] http://www.flashrom.org/mailman/listinfo/flashrom
