UM10503
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User manual
Rev. 1.3 — 6 July 2012
1200 of 1269
NXP Semiconductors
UM10503
Chapter 47: LPC43xx EEPROM memory
47.5.1 EEPROM control registers
47.5.1.1 EEPROM command register
The EEPROM command register is used to trigger an erase/program operation on the
EEPROM device.
47.5.1.2 EEPROM read wait state register
The EEPROM has no awareness of absolute time, while for EEPROM operations several
minimum absolute timing constraints have to be met. Therefore the EEPROM can only
derive time from its clock by frequency division.
The EEPROM read wait state register is used to define wait states for the AHB read
operation in functional mode only. In JTAG mode the PHASE1 and PHASE2 fields of the
EEPROM wait state register EEWSTATE are used.
Program the wait state fields to appropriate values in this wait state register for EEPROM
operation. The fields are -1 encoded, so programming zero will result in a one cycle wait
state.
The register contains two fields, each representing a minimum duration of a phase of the
EEPROM read. The appropriate values for each field are determined as follows:
(wait1) x Tclk
duration
Table 1067.EEPROM command register (CMD - address 0x4000 E000) bit description
Bits
Symbol
Description
Reset
value
2:0
CMD
Command. Read data shows the last command executed on the
EEPROM.
110 = erase/program page
All other values are reserved.
0
31:3
-
Reserved. Read value is undefined, only zero should be written.
NA
Table 1068.EEPROM read wait state register (RWSTATE - address 0x4000 E008) bit
description
Bits
Symbol
Description
Reset
value
7:0
RPHASE2
Wait states 2 (minus 1 encoded).
The number of system clock periods to meet the read operations
TRPHASE2 duration.
0
15:8
RPHASE1
Wait states 1 (minus 1 encoded).
The number of system clock periods to meet a duration equal to
TRPHASE1.
0
31:16
-
Reserved. Read value is undefined, only zero should be written.
NA