NXP Semiconductors
PT2001SWUG
PT2001 programming guide and instruction set
PT2001SWUG
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2019. All rights reserved.
User guide
Rev. 3.0 — 29 April 2019
118 / 153
stdrm
Description:
Sets the Data RAM read mode.
The possible read modes according to the ModeDRM operand are:
dram_word_mode: all 16 bits are accessed
dram_lowbyte _mode: only the 8 LSBs of the source Data RAM are accessed. The
result is available in the 8 lower bits of the destination register. The upper 8 bits of the
destination register is set to 00h.
dram_highbyte_mode: only the 8 MSBs of the source Data RAM are accessed. The
result is available in the 8 lower bits of the destination register. The upper 8 bits of the
destination register is set to 00h.
dram_swapbyte_mode: the 8 LSBs and 8 MSBs of the source dram are accessed
swapped and is available at the destination register. This read mode is valid after the
load and ldcd instructions following this stdrm instruction.
The ModeDRM reset value is word.
Assembler syntax:
stdrm ModeDRM;
Operands:
•
ModeDRM – Operand defines the Data RAM read access
Operand label
Operand description
Operand binary value
word
dram_word_mode
00
low
dram_lowbyte _mode:
01
high
dram_highbyte_mode
10
swap
dram_swapbyte_mode
11
Table 104. stdrm instruction format
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
0
1
1
0
1
0
1
1
0
0
0
0
0
ModeDRM