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uni-t-dmm: Fix UT61E bug related to the UNI-T UD-D04 cable. 

This fixes bug #136.
This commit is contained in:
Uwe Hermann 2013-08-06 23:25:18 +02:00
parent ee2cc2d4dc
commit 4d7ddff75b
2 changed files with 27 additions and 4 deletions
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11
hardware/uni-t-dmm/api.c
View File

@ -76,7 +76,16 @@ SR_PRIV struct dmm_info udmms[] = {
&uni_t_ut61d_driver_info, receive_data_UNI_T_UT61D,
},
{
"UNI-T", "UT61E", 19230,
/*
* Important: The actual baudrate of the Cyrustek ES51922 chip
* used in this DMM is 19230. However, the WCH CH9325 chip
* (UART to USB/HID) used in (some versions of) the UNI-T
* UT-D04 cable doesn't support 19230 baud. It only supports
* 19200, and setting an unsupported baudrate will result in
* the default of 2400 being used (which will not work with
* this DMM, of course).
*/
"UNI-T", "UT61E", 19200,
ES51922_PACKET_SIZE, NULL,
sr_es51922_packet_valid, sr_es51922_parse,
NULL,

20
hardware/uni-t-dmm/protocol.c
View File

@ -220,10 +220,24 @@ static int get_and_handle_data(struct sr_dev_inst *sdi, int dmm, void *info)
devc->bufoffset = 0;
/* Append the 1-7 data bytes of this chunk to pbuf. */
/*
* Append the 1-7 data bytes of this chunk to pbuf.
*
* Special case:
* DMMs with Cyrustek ES51922 chip need serial settings of
* 19230/7o1. The WCH CH9325 UART to USB/HID chip used in (some
* versions of) the UNI-T UT-D04 cable however, will also send
* the parity bit to the host in the 8-byte data chunks. This bit
* is encoded in bit 7 of each of the 1-7 data bytes and must thus
* be removed in order for the actual ES51922 protocol parser to
* work properly.
*/
num_databytes_in_chunk = buf[0] & 0x0f;
for (i = 0; i < num_databytes_in_chunk; i++)
pbuf[devc->buflen++] = buf[1 + i];
for (i = 0; i < num_databytes_in_chunk; i++, devc->buflen++) {
pbuf[devc->buflen] = buf[1 + i];
if (udmms[dmm].packet_parse == sr_es51922_parse)
pbuf[devc->buflen] &= ~(1 << 7);
}
/* Now look for packets in that data. */
while ((devc->buflen - devc->bufoffset) >= udmms[dmm].packet_size) {