Datasheet

Pinout and Signal Descriptions
Technical Data MC68HC912D60A — Rev. 3.1
60 Pinout and Signal Descriptions Freescale Semiconductor
3.6.12 Port Pull-Up Pull-Down and Reduced Drive
MCU ports can be configured for internal pull-up. To reduce power
consumption and RFI, the pin output drivers can be configured to
operate at a reduced drive level. Reduced drive causes a slight increase
in transition time depending on loading and should be used only for ports
which have a light loading. Table 3-4 summarizes the port pull-up/pull-
down default status and controls.
Table 3-4. Port Pull-Up, Pull-Down 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 Pull-up PUCR ($000C) PUPA Disabled RDRIV ($000D) RDPA Full drive
Port B Pull-up PUCR ($000C) PUPB Disabled RDRIV ($000D) RDPB Full drive
Port E:
PE7,
PE[3:2]
Pull-up PUCR ($000C) PUPE Enabled RDRIV ($000D) RDPE Full drive
PE[1:0] Pull-up PUCR ($000C) PUPE Enabled —
PE[6:4] None — RDRIV ($000D) RDPE Full drive
Port G
Pull-up or
Pull-
down
(1)
PUCR ($000C) PUPG Enabled RDRIV ($000D) RDPG Full drive
Port H
Pull-up or
Pull-
down
(2)
PUCR ($000C) PUPH Enabled RDRIV ($000D) RDPH Full drive
Port P Pull-up PWCONT ($0054) PUPP Disabled PWCONT ($0054) RDPP Full drive
PS[1:0] Pull-up PURDS ($00D9) PUPS0 Disabled PURDS ($00DB) RDPS0 Full drive
PS[3:2] Pull-up PURDS ($00D9) PUPS1 Disabled PURDS ($00DB) RDPS1 Full drive
PS[7:4] Pull-up PURDS ($00D9) PUPS2 Disabled PURDS ($00DB) RDPS2 Full drive
Port T Pull-up TMSK2 ($008D) PUPT Disabled TMSK2 ($008D) TDRB Full drive
PortCAN[1]:
TxCAN
None — —
PortCAN[0]:
RxCAN
Pull-up Always enabled —
Port
CAN[7:2]
Pull-up
PCTLCAN
($013D)
PUPCAN Disabled PCTLCAN ($013D) RDPCAN Full drive
Port AD0 None — —
Port AD1 None — —
1. Pull-Up when PGUPD input pin is high, Pull-down when PGUPD input pin is low.
In the 80-pin version, PGUPD is internally tied to VDD, hence PG4 is pulled up.
2. Pull-Up when PHUPD input pin is high, Pull-down when PHUPD input pin is low.
In the 80-pin version, PHUPD is internally tied to VSS, hence PH4 is pulled down.