ST20-GP1 View Datasheet(PDF) - STMicroelectronics
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ST20-GP1 Datasheet PDF : 116 Pages
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ST20-GP1
9.5 EMI configuration registers
Configuration parameters are stored in registers which are mapped into the device address space.
They may be accessed using devsw (device store word) and devlw (device load word) instructions.
The base addresses for the EMI registers are given in the Memory Map chapter.
EMIConfigData0-3 registers
The EMIConfigData0-3 registers contain configuration data for each of the EMI banks. The format
of each of the EMIConfigData0-3 registers is identical and is shown in Table 9.4.
EMIConfigData0-3
EMI base address + #00, #04, #08, #0C
Bit
Bit field
0
MemWaitEnable
3:1
DataDriveDelay
4
BusWidth
8:5
10:9
14:11
18:15
22:19
26:23
30:27
31
AccessDuration
BusReleaseTime
CEe1Time
CEe2Time
OEe1Time
WBe1Time
WBe2Time
Function
Enables the MemWait pin.
Drive delay of data bus for writes.
Bus width of the bank (8 or 16 bits).
BusWidth Bank width
0
16 bits
1
8 bits
Duration of the external access.
Duration bus release time.
Delay from access start to notMemCE falling edge.
Delay from notMemCE rising edge to end of access.
Delay from access start to notMemOE falling edge.
Delay from access start to notMemWB falling edge.
Delay from notMemWB rising edge to end of access.
Reserved
Read/Write
Units
-
Phases
-
Cycles
Cycles
Phases
Phases
Phases
Phases
Phases
-
Table 9.4 EMIConfigData0-3 register format - 1 per bank
EMIConfigLock register
The EMIConfigLock register is provided to write protect the EMIConfigData0-3 registers (further
writes to these registers are ignored). This bit is set by performing a devsw instruction to the given
address; the write data is ignored.
This register, once set, can only be cleared by resetting the ST20-GP1.
EMIConfigLock
EMI base address + #10
Write only
Bit
Bit field
Function
0
ConfigLock
When set, the EMIConfigData0-3 registers are read only.
Table 9.5 EMIConfigLock register format
EMIConfigStatus register
The EMIConfigStatus register is provided to indicate which registers have been written to and the
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