668-0011 Rabbit Semiconductor, 668-0011 Datasheet - Page 154

• 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

18.3 Operation
18.3.1 Asynchronous Mode
The steps to set up Serial Ports E – F for asynchronous operation are identical to those
described in Section 17.3.1 to set up Serial Ports A – D.
18.3.2 HDLC Mode
The following steps explain how to set up Serial Ports E – F for the HDLC mode. When the
internal clock is selected, the Rabbit 3000 is in control of all transmit and receive operations,
so an interrupt is not required. When an external clock is selected, operations can be handled
by either polling the status byte or by a serial port interrupt; the performance will be better
with an interrupt.
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 (data encoding, idle line condition, under-
5. Write the desired divider value to TATxR for the appropriate serial port. The overall
6. To start transmission of a packet, write the first byte to SxDR. If an internal clock is
7. Continue writing bytes when space is available in the transmit buffer until the final byte
8. The receiver will be synchronized on flag bytes and will reset the CRC. By monitoring
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port function register (PGFR).
Also select the interrupt priority.
run behavior, and combined or separate clocks).
clock divider will be the value in the appropriate register plus one.
selected, the transmission will begin immediately; if an external clock is selected the
transmission will begin when the clock is detected.
of the packet. If a CRC is to be appended to the packet, write the final byte to SxAR. If
no CRC is required, write the final byte to SxLR and just a closing flag will be appended.
If it is desirable to abort the current packet, write 11 to bits 6–7 of SxCR, and an abort
pattern will be transmitted.
the received bytes, decisions can be made about the incoming packet; if it is not desired
(i.e., it is not addressed to this device), writing a 01 to bits 6–7 of SxCR will force the
receiver back into the flag search mode.
Rabbit 3000 Microprocessor User’s Manual