AT32UC3C2512C Automotive Atmel Corporation, AT32UC3C2512C Automotive Datasheet - Page 678

• Manufacturer Part Number: AT32UC3C2512C Automotive
• Manufacturer: Atmel Corporation

26.8.9
Name:
Access Type:
Offset:
Reset Value:
• DLYBCT: Delay Between Consecutive Transfers
• DLYBS: Delay Before SPCK
• SCBR: Serial Clock Baud Rate
9166C–AVR-08/11
31
23
15
7
This field defines the delay between two consecutive transfers with the same peripheral without removing the chip select. The
delay is always inserted after each transfer and before removing the chip select if needed.
When DLYBCT equals zero, no delay between consecutive transfers is inserted and the clock keeps its duty cycle over the
character transfers.
Otherwise, the following equation determines the delay:
This field defines the delay from NPCS valid to the first valid SPCK transition.
When DLYBS equals zero, the NPCS valid to SPCK transition is 1/2 the SPCK clock period.
Otherwise, the following equations determine the delay:
In Master Mode, the SPI Interface uses a modulus counter to derive the SPCK baud rate from the CLK_SPI. The Baud rate is
selected by writing a value from 1 to 255 in the SCBR field. The following equations determine the SPCK baud rate:
Writing the SCBR field to zero is forbidden. Triggering a transfer while SCBR is zero can lead to unpredictable results.
At reset, SCBR is zero and the user has to write it to a valid value before performing the first transfer.
If a clock divider (SCBRn) field is set to one and the other SCBR fields differ from one, access on CSn is correct but no correct
access will be possible on other CS.
Delay Between Consecutive Transfers
Delay Before SPCK
SPCK Baudrate
Chip Select Register 0
30
22
14
6
CSR0
Read/Write
0x30
0x00000000
=
BITS
CLKSPI
---------------------
=
SCBR
-------------------- -
CLKSPI
DLYBS
29
21
13
5
=
32
----------------------------------- -
28
20
12
4
CLKSPI
×
DLYBCT
DLYBCT
DLYBS
SCBR
CSAAT
27
19
11
3
CSNAAT
26
18
10
2
NCPHA
25
17
9
1
AT32UC3C
CPOL
24
16
8
0
678