em78p5830aa ELAN Microelectronics Corp, em78p5830aa Datasheet - Page 21

• Manufacturer Part Number: em78p5830aa
• Description: 8-bit Micro-controller 8-bit Micro-controller
• Manufacturer: ELAN Microelectronics Corp

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* This specification is subject to be changed without notice.
VII.3 Special Purpose Registers
A (Accumulator)
CONT (Control Register)
P70EG
Internal data transfer, or instruction operand holding
It's not an addressable register.
Bit 0 ~ Bit 2 (PSR0 ~ PSR2) : TCC/WDT prescaler bits
Bit 3(PAB) : Prescaler assignment bit
Bit 5(TS) : TCC signal source
Bit 6 (INT) : INT enable flag
Bit 7(P70EG) : interrupt edge type of P70
CONT register is readable (CONTR) and writable (CONTW).
TCC and WDT :
Bit 4(RETBK) : Return value backup control for interrupt routine
0/1
0/1
When this bit is set to 1, the CPU will store ACC,R3 status and R5 PAGE automatically after an interrupt is
triggered. And it will be restored after instruction RETI. When this bit is set to 0, the user need to store ACC,
R3 and R5 PAGE in user program.
0
1
0
1
0
1
There is an 8-bit counter available as prescaler for the TCC or WDT. The prescaler is available for the TCC
only or WDT only at the same time.
An 8 bit counter is available for TCC or WDT determined by the status of the bit 3 (PAB) of the CONT
register.
See the prescaler ratio in CONT register.
Fig.8 depicts the circuit diagram of TCC/WDT.
7
PSR2
0
0
0
0
1
1
1
1
internal instruction cycle clock
16.384kHz
interrupt masked by DISI or hardware interrupt
interrupt enabled by ENI/RETI instructions
P70 's interruption source is a rising edge signal.
P70 's interruption source is a falling edge signal.
TCC/WDT
disable/enable
INT
6
PSR1
0
0
1
1
0
0
1
1
TS
5
PSR0
0
1
0
1
0
1
0
1
RETBK
4
TCC rate
1:128
1:256
1:16
1:32
1:64
1:2
1:4
1:8
PAB
3
19
WDT rate
1:128
1:16
1:32
1:64
1:1
1:2
1:4
1:8
PSR2
2
PSR1
1
PSR0
0
8-bit Micro-controller
12/1/2004 V1.6
EM785830AA