ATEVK1104 Atmel, ATEVK1104 Datasheet - Page 203

• Manufacturer Part Number: ATEVK1104
• Description: KIT DEV/EVAL FOR AVR32 AT32UC3A
• Manufacturer: Atmel
• Series: AVR®32r
• Type: MCUr

Specifications of ATEVK1104

• Contents: Evaluation Board, Software and Documentation
• Processor To Be Evaluated: AT32UC3A3
• Data Bus Width: 32 bit
• Interface Type: USB, SPI, USART
• Silicon Manufacturer: Atmel
• Core Architecture: AVR
• Core Sub-architecture: AVR UC3
• Silicon Core Number: AT32UC3A3256
• Silicon Family Name: AVR
• Kit Contents: Board CD Docs
• Rohs Compliant: Yes
• For Use With/related Products: AT32UC3A3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

23.7.3.7
Figure 23-8. Peripheral Deselection
32058J-AVR32-04/11
Write SPI_TDR
Write SPI_TDR
Write SPI_TDR
NPCS[0..3]
NPCS[0..3]
NPCS[0..3]
TDRE
TDRE
TDRE
Peripheral Deselection
A
A
A
DLYBCT
DLYBCT
DLYBCT
When operating normally, as soon as the transfer of the last data written in TDR is completed,
the NPCS lines all rise. This might lead to runtime error if the processor is too long in responding
to an interrupt, and thus might lead to difficulties for interfacing with some serial peripherals
requiring the chip select line to remain active during a full set of transfers.
To facilitate interfacing with such devices, the Chip Select Register can be programmed with the
CSAAT bit (Chip Select Active After Transfer) at 1. This allows the chip select lines to remain in
their current state (low = active) until transfer to another peripheral is required.
Figure 23-8
CSAAT = 0
DLYBCS
DLYBCS
DLYBCS
PCS = B
PCS=A
shows different peripheral deselection cases and the effect of the CSAAT bit.
PCS = A
A
B
A
A
A
A
DLYBCT
DLYBCT
DLYBCT
CSAAT = 1
DLYBCS
DLYBCS
PCS = B
PCS = A
A
A
PCS = A
DLYBCS
AT32UC3A
A
A
B
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