CH Tech EM405D - Manual (Page 25)

19
4.3.2 Write Data command
The Write Data command writes data to an EM405D control register or to a register residing on
an M-module. The command consists of seven bytes including the command-id, the module to
which the data should be written, an address space selector, the access width, the address, and
two data bytes. The return value consists of a single status byte.
Command Syntax:
0x20 md as ws ad dh dl
Return:
SC
where
md = module (0 = EM405D control, 1 = M-module A, 2 = M-module B)
as = address space (0 = I/O, 1 = future use)
ws = word size (2 = 16-bit word, other values for future use)
ad = address (0 to FF)
dh = data (MSB)
dl = data (LSB)
SC = Status Code
Example (values shown hex):
To write the data value 0x1234 to M-module A, send the following command:
Command: cd md as ws ad dh dl
Send: 20 01 00 02 06 12 34
Receive: 00 (if successful)
4.3.3 Read Data command
The Read Data command reads data from an EM405D control/status register or from a register
residing on an M-module. The command consists of five bytes including the command-id, the
module from which the data should be read, as address space selector, the access width and the
address from which to read. The return value consists of two data bytes followed by a single
status byte.
Command Syntax:
0x30 md as ws ad
Return:
dh dl SC
where
md = module (0 = EM405D control, 1 = M-module A, 2 = M-module B)
as = address space (0 = I/O, 1 = future use)
ws = word size (2 = 16-bit word, other values for future use)
ad = address (0 to FF)
dh = data (MSB)
dl = data (LSB)
SC = Status Code