668-0011 Rabbit Semiconductor, 668-0011 Datasheet - Page 138

• 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

17.3.2 Clocked Serial Mode
The following steps explain how to set up Serial Ports A – D for the clocked serial mode.
When the internal clock is selected, the Rabbit 3000 is in control of all transmit and receive
operations. When an external clock is selected, the other device controls all transmit and
receive operation. For both situations the decision between polling and interrupt-driven
methods is application-dependent.
1. Write the interrupt vector for the interrupt service routine to the internal interrupt table.
2. Set up the desired data transmit and clock pins by writing to the appropriate parallel
3. Select the appropriate mode by writing to SxCR (receive input port and clock source).
4. Select additional options by writing to SxER (clock polarity, bit order, and clock source
5. Write the desired divider value to TATxR for the appropriate serial port.
6. There are two methods to transfer a byte:
7. To receive a byte, write 01 to bits 6-7 of SxCR to start the receive operation. If the
128
port function register (PCFR or PDFR).
Also select the interrupt priority.
if external).
If the internal clock is selected, the transmission will begin immediately; if an external
clock is selected, the transmission will begin when the clock is detected.
internal clock is selected, the clock will begin immediately and the data will be read; if
an external clock is selected, the receive will occur when the clock is detected.
write the byte to SxDR and then write 10 (or 11) to bits 6–7 of SxCR to enable the
transfer;
write the byte to SxAR which will automatically start the transfer.
Rabbit 3000 Microprocessor User’s Manual