MC68HC11F1/FC0
MOTOROLA
MC68HC11FTS/D
51
SPR[1:0] — SPI Clock Rate Selects
These two bits select the SPI clock (SCK) rate when the device is configured as a master. When the
device is configured as a slave, the bits have no effect. Refer to Table 23.
NOTE
The SPRBYP bit in OPT2 on the MC68HC11FC0 allows the SPI baud rate counter
to be bypassed. This permits a maximum master mode baud rate equal to the E-
clock frequency on the MC68HC11FC0. SPRBYP is not present on the
MC68HC11F1.
SPIF — SPI Transfer Complete Flag
SPIF is set when an SPI transfer is complete. It is cleared by reading SPSR with SPIF set, followed by
a read or write of SPDR.
WCOL — Write Collision
WCOL is set when SPDR is written while a transfer is in progress. It is cleared by reading SPSR with
WCOL set, followed by a read or write of SPDR.
0 = No write collision
1 = Write collision
Bit 5 — Not Implemented. Reads always return zero and writes have no effect.
MODF — Mode Fault
A mode fault terminates SPI operation. Set when SS is pulled low while MSTR = 1. MODF is cleared
by reading SPSR read with MODF set, followed by a write to SPCR.
0 = No mode fault
1 = Mode fault
Bits [3:0] — Not Implemented. Reads always return zero and writes have no effect.
Incoming SPI data is double buffered. Outgoing SPI data is single buffered.
Table 23 SPI Baud Rates
Input
Frequency
SPR[1:0] = 00
SPR[1:0] = 01
SPR[1:0] = 10
SPR[1:0] = 11
1 MHz
500 kbps
250 kbps
62.5 kbps
31.25 kbps
2 MHz
1 Mbps
500 kbps
125 kbps
62.5 kbps
3 MHz
1.5 Mbps
750 kbps
187.5 kbps
93.75 kbps
4 MHz
2 Mbps
1 Mbps
250 kbps
125 kbps
5 MHz
2.5 Mbps
1.25 Mbps
312.5 kbps
156.25 kbps
6 MHz
3 Mbps
1.5 Mbps
375 kbps
187.5 kbps
Any E
E/2
E/4
E/16
E/32
SPSR — SPI Status Register
$x029
Bit 7
6
5
4
3
2
1
Bit 0
SPIF
WCOL
0
MODF
0
0
0
0
RESET:
0
0
0
0
0
0
0
0
SPDR — SPI Data Register
$x02A
Bit 7
6
5
4
3
2
1
Bit 0
Bit 7
6
5
4
3
2
1
Bit 0
Содержание Semiconductor MC68HC11F1
Страница 67: ...MC68HC11F1 FC0 MOTOROLA MC68HC11FTS D 67 ...