ES51985
6000 Count AUTO DMM
4. Serial Data Output
The serial data sent to SDO pin twice every A/D conversion cycle. The data format
complies with JIS 7Bits transmission code with a baud rate of 19230. The host can use
RS232 interface to read the data. A single data packet includes a start bit (always 0), 7
data bits, an odd parity check bit, and a stop bit (always 1). The high and low voltage
levels correspond to DGND and V- respectively. SDO remains at 1 (high) when it is
inactive. Hence the start bit (0) could be used as the triggering signal to begin the
reading process. The following figure shows the data format of a single packet. The
LSB is sent first and the MSB is sent last.
single package
0V
p
D0 ~D6
MSB
0
P 1
-3V
LSB
One data block consists of 11 packets, or 110 bits. The following figure shows the
format of a data block. The range packet indicates the full scale range of the meter.
Digit 3 through digit 0 are just the digits on the LCD panel. The function packet
indicates the measurement mode of the meter. Status, option 1 and option 2 give the
status of the meter. CR and LF are delimiters used to separate the blocks.
all package
p
p
p
0
1 0
1 0
1
range
digit1
status
digit3
digit2
p
p
p
p
p
p
0
0
1 0
1 0
1 0
1 0
1
1
digit0
function
option2
option1
p
p
0
1 0
1
CR
LF
12
07/01/02
CYRUSTEK [ Cyrustek corporation ]
