Programmable Four-Channel Communications Controller
—
CD2481
Datasheet
71
Bit 1:0 - Test Mode Select
The Auxiliary Instruction Registers hold the instruction that will be executed on the next
instruction cycle. When single stepping, these registers are loaded with the desired instruction and
then the single step command is issued.
6.1.2
Download Code Example
The following pages give a
‘
C
’
program example of how to perform a download operation. The
code opens a file which contains the microcode data (stored in ASCII Hex format) and then
sequentially loads the internal RAM with the data. The code requires that the microcode data be in
contiguous form. The routine is written in Borland TurboC
for the MS-DOS environment; it
should be easily ported to other environments. The microcode image is named
“
code_xx.hl
”
, where
MPU Test Control Register - Write Only) {MTCR}
F3
F1
B
W
7
6
5
4
3
2
1
0
n/u
n/u
n/u
n/u
n/u
TRAS
TMS1
TMS0
TMS1
TMS0
Mode selected
0
0
Normal mode. Select internal ROM execution
0
1
Select auxiliary instruction.
1
0
Select emulation write mode.
1
1
Select emulation read mode.
Auxiliary Instruction Register Low (write only) {AIRl}
F0
F2
B
W
7
6
5
4
3
2
1
0
Inst[7]
Inst[6]
Inst[5]
Inst[4]
Inst[3]
Inst[2]
Inst[1]
Inst[0]
Auxiliary Instruction Register Middle (write only) {AIRm}
F1
F3
B
W
7
6
5
4
3
2
1
0
Inst[15]
Inst[14]
Inst[13]
Inst[12]
Inst[11]
Inst[10]
Inst[9]
Inst[8]
Auxiliary Instruction Register High (write only) {AIRh}
F2
F0
B
W
7
6
5
4
3
2
1
0
n/u
n/u
n/u
n/u
n/u
n/u
Inst[17]
Inst[16]