C8051F336/7/8/9
SFR Definition 23.2. SPI0CN: SPI0 Control
Bit
7
SPIF
R/W
0
6
WCOL
R/W
0
5
MODF
R/W
0
4
RXOVRN
R/W
3
2
1
0
SPIEN
R/W
0
Name
Type
Reset
NSSMD[1:0]
R/W
TXBMT
R
1
0
0
1
SFR Address = 0xF8; Bit-Addressable
Bit
Name
Function
7
SPIF
SPI0 Interrupt Flag.
This bit is set to logic 1 by hardware at the end of a data transfer. If interrupts are
enabled, setting this bit causes the CPU to vector to the SPI0 interrupt service rou-
tine. This bit is not automatically cleared by hardware. It must be cleared by soft-
ware.
6
5
4
WCOL
MODF
Write Collision Flag.
This bit is set to logic 1 by hardware (and generates a SPI0 interrupt) to indicate a
write to the SPI0 data register was attempted while a data transfer was in progress.
It must be cleared by software.
Mode Fault Flag.
This bit is set to logic 1 by hardware (and generates a SPI0 interrupt) when a mas-
ter mode collision is detected (NSS is low, MSTEN = 1, and NSSMD[1:0] = 01).
This bit is not automatically cleared by hardware. It must be cleared by software.
RXOVRN
Receive Overrun Flag (valid in slave mode only).
This bit is set to logic 1 by hardware (and generates a SPI0 interrupt) when the
receive buffer still holds unread data from a previous transfer and the last bit of the
current transfer is shifted into the SPI0 shift register. This bit is not automatically
cleared by hardware. It must be cleared by software.
3:2 NSSMD[1:0] Slave Select Mode.
Selects between the following NSS operation modes:
(See Section 23.2 and Section 23.3).
00: 3-Wire Slave or 3-Wire Master Mode. NSS signal is not routed to a port pin.
01: 4-Wire Slave or Multi-Master Mode (Default). NSS is an input to the device.
1x: 4-Wire Single-Master Mode. NSS signal is mapped as an output from the
device and will assume the value of NSSMD0.
1
0
TXBMT
SPIEN
Transmit Buffer Empty.
This bit will be set to logic 0 when new data has been written to the transmit buffer.
When data in the transmit buffer is transferred to the SPI shift register, this bit will
be set to logic 1, indicating that it is safe to write a new byte to the transmit buffer.
SPI0 Enable.
0: SPI disabled.
1: SPI enabled.
182
Rev. 0.2
SILICON [ SILICON ]
