CLOCK GENERATION AND POWER MANAGEMENT
5-14
Example 5-1. Initializing the Power Management Unit for Power-Save Mode
$mod186
name
example_PSU_code
;FUNCTION:
This function reduces CPU power consumption
;
by dividing the CPU operating frequency by a
;
divisor.
; SYNTAX:
extern void far power_save(int divisor);
; INPUTS:
divisor - This variable represents F0, F1 and F2
;
of PWRSAV.
; OUTPUTS:
None
; NOTE:
Parameters are passed on the stack as required
;
by high-level languages
;substitute register offset
PWRSAV
equ xxxxH
;Power-Save Register
RFTIME
equ xxxxH
;Refresh Interval Count
;Register
RFCON
equ xxxxH
;Refresh Control Register
PSEN
equ 8000H
;Power-Save enable bit
data
segment public 'data'
FreqTable
dw 1, 4, 8, 16, 32, 64, 0, 0
data
ends
lib_80C186
segment public 'code'
assume cs:lib_80C186, ds:data
public _power_save
_power_save
proc far
push bp
;save caller's bp
mov bp, sp
;get current top of stack
push ax
;save registers that will
push dx
;be modified
_divisor
equ word ptr[bp+6]
;get parameter off the
;stack
mov dx, RFTIME
;get current DRAM refresh
in ax, dx
;rate
and ax, 01ffh
;mask off unwanted bits
div FreqTable[_divisor]
;divide refresh rate
;by _divisor
out dx, ax
;set new refresh rate
mov dx, PWRSAV
;select Power-Save Register
mov ax, _divisor
;get divisor
and ax, 7
;mask off unwanted bits
or ax, PSEN
;set enable bit
out dx, ax
;divide frequency
pop dx
;restore saved registers
pop bx
pop ax
pop bp
;restore caller's bp
ret
_power_save
endp
lib_80C186
ends
end
Содержание 80C186XL
Страница 1: ...80C186XL 80C188XL Microprocessor User s Manual...
Страница 2: ...80C186XL 80C188XL Microprocessor User s Manual 1995...
Страница 18: ...1 Introduction...
Страница 19: ......
Страница 27: ......
Страница 28: ...2 Overview of the 80C186 Family Architecture...
Страница 29: ......
Страница 79: ......
Страница 80: ...3 Bus Interface Unit...
Страница 81: ......
Страница 127: ......
Страница 128: ...4 Peripheral Control Block...
Страница 129: ......
Страница 137: ......
Страница 138: ...5 ClockGenerationand Power Management...
Страница 139: ......
Страница 154: ...6 Chip Select Unit...
Страница 155: ......
Страница 178: ...7 Refresh Control Unit...
Страница 179: ......
Страница 193: ......
Страница 194: ...8 Interrupt Control Unit...
Страница 195: ......
Страница 227: ......
Страница 228: ...9 Timer Counter Unit...
Страница 229: ......
Страница 253: ......
Страница 254: ...10 Direct Memory Access Unit...
Страница 255: ......
Страница 283: ......
Страница 284: ...11 Math Coprocessing...
Страница 285: ......
Страница 302: ...12 ONCE Mode...
Страница 303: ......
Страница 306: ...A 80C186 Instruction Set Additions and Extensions...
Страница 307: ......
Страница 318: ...B Input Synchronization...
Страница 319: ......
Страница 322: ...C Instruction Set Descriptions...
Страница 323: ......
Страница 371: ......
Страница 372: ...D Instruction Set Opcodes and Clock Cycles...
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Страница 396: ...Index...
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