em78p468n ELAN Microelectronics Corp, em78p468n Datasheet - Page 21

• Manufacturer Part Number: em78p468n
• Description: 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

Product Specification (V1.6) 12.31.2007
(This specification is subject to change without further notice)
6.2 Special Purpose Registers
6.2.1 A (Accumulator)
Internal data transfer operation, or instruction operand holding usually involves the
temporary storage function of the Accumulator, which is not an addressable register.
6.2.2 IOC50/P5CR (Port 5 I/O and Ports 7, 8 for LCD Segment
(Address: 05h, Bit 0 of R5 = “0”)
Bits 7~4 (IOC57~54): Port 5 I/O direction control register
Bit 3 (P8HS): Switch to high nibble I/O of Port 8 or to LCD segment output while
Bit 2 (P8LS): Switch to low nibble I/O of Port 8 or to LCD segment output while sharing
Bit 1 (P7HS): Switch to high nibble I/O of Port 7 or to LCD segment output while
Bit 0 (P7LS): Switch to low nibble I/O of Port 7 or to LCD segment output while sharing
IOC57
Bit 7
Registers of IOC Page 0 (IOC50 ~ IOCF0, Bit 0 of R5 = “0”)
IOC5x = “0”: set the relative P5.x I/O pins as output
IOC5x = “1”: set the relative P5.x I/O pin into high impedance (input pin)
P8HS = “0”: select high nibble of Port 8 as normal P8.4~P8.7
P8HS = “1”: select LCD segment output as SEG 28~SEG 31 output
P8LS = “0”: select low nibble of Port 8 as normal P8.0~P8.3
P8LS = “1”: select LCD Segment output as SEG 24~SEG 27 output
P7HS = “0”: select high nibble of Port 7 as normal P7.4~P7.7
P7HS = “1”: select LCD Segment output as SEG 20~SEG 23 output
P7LS = “0”: select low nibble of Port 7 as normal P7.0~P7.3
P7LS = “1”: select LCD segment output as SEG 16~SEG 19 output
Control Register)
IOC56
sharing pins with SEGxx/P8.x pins.
pins with SEGxx/P8.x pins
pins with SEGxx/P7.x pins
Bit 6
sharing pins with SEGxx/P7.x pins
IOC55
Bit 5
IOC54
Bit 4
P8HS
Bit 3
P8LS
Bit 2
8-Bit Microcontroller
P7HS
Bit 1
EM78P468N/L
P7LS
Bit 0
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