AT32UC3C2512C Automotive Atmel Corporation, AT32UC3C2512C Automotive Datasheet - Page 317

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

18.6.4.5
9166C–AVR-08/11
Write mode
•Null delay setup and hold
•Null pulse
•Write is controlled by NWE (MODE.WRITEMODE = 1)
If null setup parameters are programmed for NWE and/or NCS, NWE and/or NCS remain active
continuously in case of consecutive write cycles in the same memory (see
317). However, for devices that perform write operations on the rising edge of NWE or NCS,
such as SRAM, either a setup or a hold must be programmed.
Figure 18-12. Null Setup and Hold Values of NCS and NWE in Write Cycle
Programming null pulse is not permitted. Pulse must be at least written to one. A null value leads
to unpredictable behavior.
The Write Mode bit in the MODE register (MODE.WRITEMODE) of the corresponding chip
select indicates which signal controls the write operation.
Figure 18-13 on page 318
equal to one. The data is put on the bus during the pulse and hold steps of the NWE signal. The
internal data buffers are turned out after the NWESETUP time, and until the end of the write
cycle, regardless of the programmed waveform on NCS.
NBS0, NBS1,
A[AD_MSB:2]
NWE0, NWE1
A0, A1
CLK_SMC
NWE,
NCS
D[15:0]
NCSWRSETUP
NWECYCLE
NWESETUP
shows the waveforms of a write operation with MODE.WRITEMODE
NWEPULSE
NCSWRPULSE
NWECYCLE
NCSWRPULSE
NWECYCLE
NWEPULSE
Figure 18-12 on page
AT32UC3C
317