Sundance Spas ST201 - Manual (Page 82)

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Sundance Technology ST201 PRELIMINARY draft 2
EEPROMCTRL
Class....................I/O Registers, External Interface Control
Base Address ......IoBaseAddress register value
Address Offset .....0x36
Access Mode .......Read/Write
Width ...................16 bits
EepromCtrl provides the host with a method for issuing commands to the ST201’s serial EEPROM control-
ler. Individual 16-bit word locations within the EEPROM may be written, read or erased. Also, the
EEPROM’s WriteEnable, WriteDisable, EraseAll and WriteAll commands can be issued. Two-bit opcodes
and 8-bit addresses are written to this register to cause the ST201 to carry out the desired EEPROM com-
mand. If data is to written to the EEPROM, the 16-bit data word must be written to EepromData by the host
prior to issuing the associated write command. Similarly, if data is to be read from the EEPROM, the read
data will be available via EepromData register. The EEPROM is a particularly slow device. It is important
that the host wait until the EepromBusy bit is false before issuing a command to EepromCtrl. EepromCtrl
defaults to 0000h upon reset.
BIT BIT NAME BIT DESCRIPTION
7..0 EepromAddress These eight read/write bits identify one of the 256 sixteen-bit words to
be the target for the ReadRegister, WriteRegister and EraseRegister
commands. Bits 7 and 6 are further defined to identify an individual
command among the following group of four sub-commands:
sub-opcodesub-command
00WriteDisable
01WriteAII
10EraseAII
11WriteEnable
The definition of bits 7 and 6 are valid when the EepromOpcode in bits
9 and 8 equals 00.
9..8 EepromOpcode These two read/write bits specify one of three individual commands
and a single group of four sub-commands. The following table defines
the opcodes:
EepromOpcode command
00 Write Enable/Disable & Write/Erase All sub-commands
01 WriteRegister
10 ReadRegister
11 EraseRegister
14..10 Reserved Reserved for future use. Should be set to 0.
15 EepromBusy This read-only bit is asserted during the execution of EEPROM com-
mands. Further commands should not be issued to EepromCtrl nor
should data be read from EepromData while this bit is true.