Toshiba T2N - Manual (Page 131)

4.Peripheral Memory Support
118 PROSEC T2N
The contents of the user program and the register data (D) can be stored in the
EEPROM and they can be read into the main memory (RAM) by the initial load
function in the T2N or programmer operation (for maintanance).
The register data (D) in the EEPROM can be written to internal registers or be
read out from them in the T2N during RUN operation by using special
instruction XFER. The T2N can run without batteries and can be recovered
easily from error down if user program is destroyed by using the EEPROM.
The following functions are available with the EEPROM.
Function Operation Execution condition
At system initialization
when power is turned on and
ROM/RAM switch is set to
ROM
(not executed in the P-RUN
mode) Initial load Transfers the contents of the EEPROM to
the user program memory and data
registers (D0000-2047) in the main
memory (RAM).
However when the mode is transited from
HALT to RUN, other registers except
retentive specified memory is cleared.
At transition to the RUN mode
when transited to the RUN
mode and ROM/RAM switch is
set to ROM
(not executed in the P-RUN
mode)
Read/write
the data registers
in EEPROM Reads out the data registers (D) in the
EEPROM and stores in the main memory
by user program.
Writes the specified data of the main
memory into the data registers in the
EEPROM by user program. Accessed by expanded data
transfer instruction (XFER).
Write EEPROM
(by programmer) Writes the contents of the user program
(including the system information) and
the data registers(D), the timer
registers(T), the counter registers(C) and
the auxiliary relay registers(RW) in the
main memory(RAM) into the EEPROM. Executed by programmer
command “Program write to IC
card EEPROM” in the HALT
mode
Read EEPROM
(by programmer) Transfers the contents OF the EEPROM
to the user program (including the system
information) and the data registers(D),
the timer registers(T), the counter
registers(C) and the auxiliary relay
registers(RW) in the main memory(RAM). Executed by programmer
command “Program read from
IC card EEPROM” in the HALT
mode
(not executed in the P-RUN
mode)
*The P-RUN mode is when the operation switch is P-RUN.
1.Refer to 2.2 System initialization and 2.4 Scan control for details of the
initial load function.
2.The EEPROM can be written up to 100,000 times(guaranteed)
depending on the hardware. The EEPROM alarm flag(S0039) comes
ON if the EEPROM is written more than the limitation. Thereafter
operation is not guaranteed.
S0039 may come ON when power is turned OFF during writing into
EEPROM. In this case, carry out Write EEPROM command once.
Nevertherless if S0039 is ON, it is recommended that the CPU module
should be changed.
4.1
EEPROM Support
NOTE