EM78M612
Universal Serial Bus Microcontroller Series
8.2.1.3 Control Registers in Bank 0
Special purpose registers for special control purposes are also available. Except for the
Accumulator (A), these registers must be read and written by special instructions. One of
these registers, CONT, can only be read by the instruction "CONTR" and written by
"CONTW" instruction. The remaining special control registers can be read by the instruction
"IOR" and written by the instruction "IOW."
The following paragraphs only describe the general functions of the control registers. For
more detailed description, refer to Sections 8.8 to 8.10 of this spec.
A (Accumulator Register)
The accumulator is an 8-bit register that holds operands and results of arithmetic
calculations. It is not addressable.
CONT (Control Register) Default Value: (0B_0011_1111)
7
0
6
/INT
5
4
3
2
1
0
TSR2
TSR1
TSR0
PSR2
PSR1
PSR0
[NOTE] The CONT register can be read by the instruction "CONTR" and written by the
instruction “CONTW."
CONT [0~2] WatchDog Timer prescaler bits. These three bits are used as the prescaler of
WatchDog Timer.
CONT [3~5] TCC Timer prescaler bits.
The relationship between the prescaler value and these bits are as shown below:
PSR2/TSR2
PSR1/TSR1
PSR0/TSR0
TCC Rate
WDT Rate
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
1: 2
1: 4
1: 8
1: 16
1: 32
1: 64
1: 128
1: 256
1: 1
1: 2
1: 4
1: 8
1: 16
1: 32
1: 64
1: 128
This specification may change without further notice.
2004/4/28 V1.1
18
ELAN [ ELAN MICROELECTRONICS CORP ]
