em78p5842 ELAN Microelectronics Corp, em78p5842 Datasheet - Page 9

• Manufacturer Part Number: em78p5842
• Description: 8-bit Micro-controller
• Manufacturer: ELAN Microelectronics Corp

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* This specification is subject to change without notice.
VII.2 Operational Register Detail Description
* IOC register are special registers. User can use instruction
R0 (Indirect Addressing Register)
R1 (TCC)
R2 (Program Counter)
Addr IOC PAGE0
0A
0B
0C
0D
0E Interrupt mask
0F Interrupt mask
1F
3F
00
01
02
03
04
05
06
07
08
09
10
20
R0 is not a physically implemented register. It is used as indirect addressing pointer. Any instruction using R0
as register actually accesses data pointed by the RAM Select Register (R4).
Example:
Mov
Mov
Mov
Mov
:
:
“IOW” to write data or “IOR” to read data.
TCC data buffer. Increased by 16.384KHz or by the instruction cycle clock (controlled by CONT register).
Written and read by the program as any other register.
The structure is depicted in Fig.3.
Generates 4k u 13 external ROM addresses to the relative programming instruction codes.
"JMP" instruction allows the direct loading of the low 10 program counter bits.
"CALL" instruction loads the low 10 bits of the PC, PC+1, and then push into the stack.
"RET'' ("RETL k", "RETI") instruction loads the program counter with the contents at the top of stack.
Port6 I/O control
Port7 I/O control
Port9 I/O control
A, @0x20
0x04, A
A, @0xAA
0x00, A
IOC PAGE registers
;store a address at R4 for indirect addressing
;write data 0xAA to R20 at bank0 through R0
IOC PAGE1
Port6 switches
Port7 pull high
ADC control
Clock source (CN1)
Prescaler(CN1)
7
EM785840/5841/5842
8-bit Micro-controller
2004/11/10 V1.2