Datasheet

Signal Descriptions
MC68HC812A4 Data Sheet, Rev. 7
Freescale Semiconductor 23
Table 1-4. Port Pullup, Pulldown, and Reduced Drive Summary
Enable Bit Reduced Drive Control Bit
Port
Name
Resistive
Input Loads
Register
(Address)
Bit Name
Reset
State
Register
(Address)
Bit
Name
Reset
State
Port A Pullup PUCR ($000C) PUPA Enabled RDRIV ($000D) RDPAB Full drive
Port B Pullup PUCR ($000C) PUPB Enabled RDRIV ($000D) RDPAB Full drive
Port C Pullup PUCR ($000C) PUPC Enabled RDRIV ($000D) RDPC Full drive
Port D Pullup PUCR ($000C) PUPD Enabled RDRIV ($000D) RDPD Full drive
Port E:
PE7, PE3,
PE2, PE0
Pullup PUCR ($000C) PUPE Enabled RDRIV ($000D) RDPE Full drive
Port E:
PE1
Pullup Always enabled RDRIV ($000D) RDPE Full drive
Port E:
PE4
None — RDRIV ($000D) RDPE Full drive
Port E:
PE6 and PE5
Pulldown Enabled during reset — — —
Port F Pullup PUCR ($000C) PUPF Enabled RDRIV ($000D) RDPF Full drive
Port G Pullup PUCR ($000C) PUPG Enabled RDRIV ($000D) RDPG Full drive
Port H Pullup PUCR ($000C) PUPH Enabled RDRIV ($000D) RDPH Full drive
Port J
Pullup/down
(1)
1. Pullup or pulldown devices for each port J pin can be selected with the PUPSJ register ($002D). After reset, pulldowns are
selected for all port J pins but must be enabled with PULEJ register.
PULEJ ($002E) PULEJ[7:0] Disabled RDRIV ($000D) RDPJ Full drive
Port S Pullup SP0CR2 ($00D1) PUPS Enabled SP0CR2 ($00D1) RDS Full drive
Port T Pullup TMSK2 ($008D) PUPT Enabled TMSK2 ($008D) RDPT Full drive
Port AD None — —
BKGD Pullup — — Enabled — — Full drive