PKP
VS1000 P
ROGRAMMER
’
S
G
UIDE
VSMPG
17
Byte-wide bus/Nand Flash controller
v1.0 2006-05-10
17.1
General
The byte-wide bus peripheral implements a nand flash controller with vsdsp peripheral
bus interface. The peripheral can be configured for different speed/size memory devices.
The device has internal ECC calculation which provides the error detection data for the
dsp.
VS1000 Nand Flash interface uses chip’s master clock to generated IO signal trans-
actions. Therefore changing master clock frequency changes also the interfaces’s AC
waveforms.
The Nand Flash controller requires that dsp controls the command latch enable (CLE)
and address latch enable (ALE) pins directly (as GPIO). Memory chip enable (NFCE)
can be controlled either as GPIO or automatically by the Nand Flash controller. Other
signals are generated with NF peripheral.
•
NFCE : Chip enable, active low
•
NFWR : write enable, active low
•
NFRD : Read enable, active low
•
NFDIO : 8-bit data bus, sampled at rising edge of NFRD and written at falling edge
of NFWR
•
NFRDY : Ready/xBusy signal from flash chip. This signal must be at logic HIGH
state before read or write operation is started (command, address or data trans-
action). NFRDY requires external 10 kOhm pull-up resistor.
The nand flash IO signals can be read at any time through GPIO0_IDATA.
The peripheral provides clocked byte transfers of 1..32 bytes from an integrated buffer
memory freeing the DSP from having to generate clocking for each transferred byte. The
peripheral also provides standard Error Correcting Code (ECC) calculation for 1..512
byte blocks.
Configurable features include:
•
Programmable address cycles from 1 to 32
•
Programmable wait states from 0 to 63 (i.e. Read/write pulse time)
•
ECC calculation disable/enable
•
Interrupt request disable/enable
•
Chip select write mode continuous/byte-at-a-time (for LCDs)
•
1 - 512 byte blocks ECC calculation (in 16-bit words)
•
Programmable burst transactions from 1 to 32 bytes
Rev. 0.20
2011-10-04
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