em78f644nso28s ELAN Microelectronics Corp, em78f644nso28s Datasheet - Page 52

• Manufacturer Part Number: em78f644nso28s
• Description: Flash Series 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

EM78F648/644/642/641/548/544/542/541N
8-Bit Microcontroller
42 •
Bits 1 ~ 0: Not used, set to “1” all the time.
6.2 Special Function Registers
6.2.1 A (Accumulator)
Internal data transfer operation or instruction operand holding usually involves the
temporary storage function of the Accumulator. The Accumulator is not an
addressable register.
6.2.2 CONT (Control Register)
Bit 7 (INTE): INT signal edge
Bit 6 (/INT): Interrupt enable flag
Bit 5 (TS):
Bit 4 (TE):
Bit 3 (PSTE): Prescaler enable bit for TCC
INTE
Bit 7
(for EM78F644/642/641/544/542/541N Series Only)
The RF register is both readable and writable.
For F642/542N, Bit 6 ~ Bit 5, Bit 3 ~ Bit 0 are unused. Set to “1” all the time.
For F641/541N, Bit 7 ~ Bit 0 are unused. Set to “1” all the time.
Bit 6
0: Interrupt occurs at rising edge of the INT pin
1: Interrupt occurs at falling edge of the INT pin
0: Masked by DISI or hardware interrupt
1: Enabled by ENI/RETI instructions
TCC signal source
0: Internal instruction cycle clock
1: Transition on TCC pin
TCC signal edge
0: Increment if a transition from low to high takes place on the TCC pin
1: Increment if a transition from high to low takes place on the TCC pin
0: Prescaler disable bit, TCC rate is 1:1
1: Prescaler enable bit, TCC rate is set as Bit 2~Bit 0
/INT
For F641/541N, Bit 5 ~ Bit 4 are unused. Set to “0” all the time.
Bit 5
TS
Bit 4
TE
(This specification is subject to change without further notice)
NOTE
NOTE
PSTE
Bit 3
Product Specification (V1.0) 05.05.2010
PST2
Bit 2
PST1
Bit 1
PST0
Bit 0