20-668-0024 Rabbit Semiconductor, 20-668-0024 Datasheet - Page 107

• Manufacturer Part Number: 20-668-0024
• Description: IC CPU RABBIT4000 128-LQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 20-668-0024

• Processor Type: Rabbit 4000 8-bit
• Speed: 60MHz
• Voltage: 2.5V, 2.7V, 3V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 128-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Other names: 20-668-0022; 316-1078

12.1 Overview
Parallel Port E is a byte-wide port with each bit programmable for data direction and drive
level. These are simple inputs and outputs controlled and reported in the Port E Data
Register (PEDR).
All of the Parallel Port E pins have alternate output functions, and all of them can be used
as inputs to various on-chip peripherals.
When used as outputs, the Parallel Port E bits are buffered, with the data written to PEDR
transferred to the output pins on a selected timing edge. Either the peripheral clock or the
outputs of Timer A1, Timer B1, or Timer B2 can be used for this function, with each nib-
ble of the port having a separate select field to control this timing. Each bit can either be
programmed as open-drain or driven high and low.
Because of the buffered nature of Parallel Port E, using a read-modify-write type of opera-
tion can lead to old data being written to PEDR. To alleviate this potential problem, each
bit of the port can be written individually using a separate address for each bit.
Bit 7 of Parallel Port E is used as the default chip select input for the slave port when the
slave port is enabled, either for parallel bootstrap or under program control.
Chapter 12 Parallel Port E
Pin Name
PE7
PE6
PE5
PE4
PE3
PE2
PE1
PE0
Table 12-1. Parallel Port E Pin Alternate Output Functions
Alt Out 0
I7
I5
I3
I6
I4
I2
I1
I0
12. P
Alt Out 1
/LINK
/ACT
A23
A22
A21
A20
/A0
—
ARALLEL
TIMER C3
TIMER C2
TIMER C1
TIMER C0
Alt Out 2
PWM3
PWM2
PWM1
PWM0
Alt Out 3
RCLKE
SCLKD
SCLKC
TCLKE
RCLKF
TCLKF
TXE
TXF
P
ORT
E
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