mc68hc05p18a Freescale Semiconductor, Inc, mc68hc05p18a Datasheet - Page 82

• Manufacturer Part Number: mc68hc05p18a
• Description: Mc68hc05p18a Hcmos Microcontroller Unit
• Manufacturer: Freescale Semiconductor, Inc

Serial Input/Output Ports (SIOP)
9.4.2 SIOP Status Register
Technical Data
Address:
This register is located at address $000B and contains two bits.
Figure 9-4
the value of each bit after reset.
SPIF — Serial Port Interface Flag
DCOL — Data Collision Bit
Reset:
Read:
Write:
SPIF is a read-only status bit that is set on the last rising edge of SCK
and indicates that a data transfer has been completed. It has no effect
on any future data transfers and can be ignored. The SPIF bit is
cleared by reading the SSR followed by a read or write of the SDR. If
the SPIF is cleared before the last rising edge of SCK it will be set
again on the last rising edge of SCK. Reset clears the SPIF bit.
DCOL is a read-only status bit, which indicates that an illegal access
of the SDR has occurred. The DCOL bit will be set when reading or
writing the SDR after the first falling edge of SCK and before SPIF is
set. Reading or writing the SDR during this time will result in invalid
data being transmitted or received.
The DCOL bit is cleared by reading the SSR (when the SPIF bit is set)
followed by a read or write of the SDR. If the last part of the clearing
sequence is done after another transfer has started, the DCOL bit will
be set again. Reset clears the DCOL bit.
Freescale Semiconductor, Inc.
For More Information On This Product,
$000B
SPIF
Bit 7
0
Serial Input/Output Ports (SIOP)
shows the position of each bit in the register and indicates
Go to: www.freescale.com
Figure 9-4. SIOP Status Register (SSR)
= Unimplemented
DCOL
6
0
5
0
0
4
0
0
3
0
0
2
0
0
MC68HC05P18A
1
0
0
Bit 0
0
0