mc68hc05l25 Freescale Semiconductor, Inc, mc68hc05l25 Datasheet - Page 61

• Manufacturer Part Number: mc68hc05l25
• Description: M68hc05 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

7.3 Port B
Port B is an 8-bit bidirectional port that is shared with LCD frontplane drivers as shown in
Each port B pin is controlled by the corresponding bits in a data direction register and a data register. The
port B data register is located at address $0001. The port B data direction register (DDRB) is located at
address $0001 of the option map. Reset clears the DDRB. The port B data register is unaffected by reset.
The LCD frontplane drivers are enabled on reset.
Freescale Semiconductor
INTERNAL HC05
DATA BUS
WRITE OPTN: $0008
WRITE OPTN: $000A
WRITE OPTN: $0001
WRITE $0001
READ OPTN: $000A
READ OPTN: $0008
READ OPTN: $0001
READ $0001
RESET
(RST)
Figure 7-10. Port B0:B7/FP24:FP17 I/O Circuitry
DATA DIRECTION
MC68HC05L25 Data Sheet, Rev. 3.1
REGISTER BIT
REGISTER BIT
REGISTER BIT
REGISTER BIT
OPEN DRAIN
PULLUP
SYSTEM
DATA
LCD
PBE BIT
LCDCR
FP
PULLUP
LOGIC
OUTPUT
OUTPUT
Figure
R PULLUP
PIN
I/O
7-10.
Port B
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