at91rm3400 ATMEL Corporation, at91rm3400 Datasheet - Page 243

• Manufacturer Part Number: at91rm3400
• Description: Atmel Advanced At91 Arm Microcontroller
• Manufacturer: ATMEL Corporation

• PCS: Peripheral Chip Select
This field is only used if Fixed Peripheral Select is active (PS = 0).
If PCSDEC = 0:
If PCSDEC = 1:
• DLYBCS: Delay Between Chip Selects
This field defines the delay from NPCS inactive to the activation of another NPCS. The DLYBCS time guarantees non-over-
lapping chip selects and solves bus contentions in case of peripherals having long data float times.
If DLYBCS is less than or equal to six, six MCK periods (or 192 MCK periods if DIV32 is set) will be inserted by default.
Otherwise, the following equation determines the delay:
If DIV32 is 0:
If DIV32 is 1:
1790A–ATARM–11/03
PCS = xxx0
PCS = xx01
PCS = x011
PCS = 0111
PCS = 1111
(x = don’t care)
NPCS[3:0] output signals = PCS
NPCS[3:0] = 1110
NPCS[3:0] = 1101
NPCS[3:0] = 1011
NPCS[3:0] = 0111
forbidden (no peripheral is selected)
Delay Between Chip Selects
Delay Between Chip Selects
=
=
DLYBCS MCK
DLYBCS
32 MCK
AT91RM3400
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