19 SPi
19-6
Seiko epson Corporation
S1C17624/604/622/602/621 TeChniCal Manual
An interrupt occurs if other interrupt conditions are met. You can inspect the SPRBF flag in the SPI interrupt
handler routine to determine whether the SPI interrupt is attributable to a receive buffer full. If SPRBF is 1, the
received data can be read from the receive data buffer by the interrupt handler routine.
For more information on interrupt processing, see the “Interrupt Controller (ITC)” chapter.
Control Register Details
19.7
7.1 List of SPI Registers
Table 19.
address
Register name
Function
0x4320
SPI_ST0
SPI Ch.0 Status Register
Indicates transfer and buffer statuses.
0x4322
SPI_TXD0
SPI Ch.0 Transmit Data Register
Transmit data
0x4324
SPI_RXD0
SPI Ch.0 Receive Data Register
Receive data
0x4326
SPI_CTL0
SPI Ch.0 Control Register
Sets the SPI mode and enables data transfer.
The SPI registers are described in detail below. These are 16-bit registers.
note: When data is written to the registers, the “Reserved” bits must always be written as 0 and not 1.
SPi Ch.
x
Status Register (SPi_ST
x
)
Register name address
Bit
name
Function
Setting
init. R/W
Remarks
SPi Ch.
x
Status
Register
(SPi_ST
x
)
0x4320
(16 bits)
D15–3 –
reserved
–
–
–
0 when being read.
D2
SPBSY
Transfer busy flag (master)
1 Busy
0 Idle
0
R
ss signal low flag (slave)
1 ss = L
0 ss = H
D1
SPRBF
Receive data buffer full flag
1 Full
0 Not full
0
R
D0
SPTBe
Transmit data buffer empty flag
1 Empty
0 Not empty
1
R
D[15:3] Reserved
D2
SPBSY: Transfer Busy Flag Bit (Master Mode)/ss Signal low Flag Bit (Slave Mode)
Master mode
Indicates the SPI transfer status.
1 (R):
Operating
0 (R):
Standby (default)
SPBSY is set to 1 when the SPI starts data transfer in master mode and is maintained at 1 while transfer
is underway. It is cleared to 0 once the transfer is complete.
Slave mode
Indicates the slave selection (#SPISS
x
) signal status.
1 (R):
Low level (this SPI is selected)
0 (R):
High level (this SPI is not selected) (default)
SPBSY is set to 1 when the master device asserts the #SPISS
x
signal to select this SPI module (slave
device). It is returned to 0 when the master device clears the SPI module selection by negating the
#SPISS
x
signal.
D1
SPRBF: Receive Data Buffer Full Flag Bit
Indicates the receive data buffer status.
1 (R):
Data full
0 (R):
No data (default)
SPRBF is set to 1 when data received in the shift register is sent to the receive data buffer (when receiv-
ing is completed), indicating that the data can be read. It reverts to 0 once the buffer data is read from
the SPI_RXD
x
register.
D0
SPTBe: Transmit Data Buffer empty Flag Bit
Indicates the transmit data buffer status.
1 (R):
Empty (default)
0 (R):
Data exists