668-0011 Rabbit Semiconductor, 668-0011 Datasheet - Page 89

• Manufacturer Part Number: 668-0011
• Description: IC MPU RABIT3000A 55.5MHZ128LQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 668-0011

• Rohs Status: RoHS non-compliant
• Processor Type: Rabbit 3000 8-Bit
• Speed: 55.5MHz
• Voltage: 2.5V, 2.7V, 3V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 128-LQFP
• Features: -
• Other names: 316-1043

11.1 Overview
Parallel Port D is a byte-wide port with each bit programmable individually for data direc-
tion and drive level. These are simple inputs and outputs controlled and reported in the
Port D Data Register (PDDR). The output registers are cascaded and timer-controlled,
making it possible to generate precise timing pulses.
Four of the Parallel Port D pins have alternate functions as Serial Ports A and B. Alternate
serial port bit assignments make it possible for the same serial port to connect to different
communications lines that are not operating at the same time.
When used as outputs, the Parallel Port D bits are buffered, with the data written to PDDR
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 nibble
of the port having a separate select field to control this timing. Each bit can either be pro-
grammed as an open-drain output or a standard output.
Because of the buffered nature of Parallel Port D, using a read-modify-write type of oper-
ation can lead to old data being written to PDDR. To alleviate this potential problem, each
bit of the port can be written individually using a separate address for each bit.
Chapter 11 Parallel Port D
Pin Name
* Introduced with Rabbit 3000A chip.
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
Serial Ports A–B
Table 11-1. Parallel Port D Alternate Pin Functions
ARXA
ARXB
—
—
—
—
—
—
Inputs
Input Capture
11. P
—
—
—
—
×
×
×
×
ARALLEL
APWM2
APWM3
PWM
—
—
—
—
—
—
*
*
Outputs
Serial Ports A–B
P
ORT
ATXA
ATXB
—
—
—
—
—
—
D
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