ST9291J6/N6 查看數據表（PDF） - STMicroelectronics
零件编号
产品描述 (功能)
生产厂家
ST9291J6/N6 Datasheet PDF : 20 Pages
| |||
ST9291
SYSTEM REGISTERS (Continued)
Stack location
Care is necessary when managing stacks as there
is no limit to stack sizes apart from the bottom of
any address space in which the stack is placed.
Consequently programmers are advised to use a
stack pointer value as high as possible, particularly
when using the Register File as a stacking area.
This will also benefit programmers who may locate
the stacks in group D using, for example the in-
struction ld R237, #223 which loads the value
Figure 1-11. System and/or User Stack in
Register Stack Mode
R255
REGISTER FILE
223 into the User Stack Pointer Low Register. The
Programmer will not need to remember to set the
Register Pointer to 208 to gain access to registers
in the D-group, a problem outlined in Register
Pointing Techniques paragraph.
Stacks may be located anywhere in the first 14
groups of the Register File (internal stacks) or the
data memory (external stacks). It is not necessary
to set the data memory using the instruction sdm
as external stack instructions automatically use the
data memory.
Figure 1-12. System and/or User Stack in
Memory Stack Mode
DATA MEMORY
SYSTEM REGISTERS
STACK POINTER L
STACK POINTER H
STACK POINTER L
STACK POINTER H
STACK
STACK
R0
VA00434
USP R236 (ECh) System Read/Write
User Stack Pointer High Byte
Reset value: undefined
7
0
USP15 USP14 USP13 USP12 USP11 USP10 USP9 USP8
USP R237 (EDh) System Read/Write
User Stack Pointer Low Byte
Reset value: undefined
7
0
USP7 USP6 USP5 USP4 USP3 USP2 USP1 USP0
SSP R238 (EEh) System Read/Write
VA00435
System Stack Pointer High Byte
Reset value: undefined
7
0
SSP15 SSP14 SSP13 SSP12 SSP11 SSP10 SSP9 SSP8
SSP R239 (EFh) System Read/Write
System Stack Pointer Low Byte
Reset value: undefined
7
0
SSP7 SSP6 SSP5 SSP4 SSP3 SSP2 SSP1 SSP0
1.2 MEMORY
17/20
®
Share Link: 