INTERNAL MEMORY
6.4 Registers Associated with the Internal Flash Memory
6
6.4.4 Flash Control Registers
Flash Control Register 1 (FCNT1)
<Address: H’0080 01E2>
b0
1
2
3
FENTRY
0
4
5
6
b7
FEMMOD
0
0
0
0
0
0
0
<After reset: H’00>
b
Bit Name
Function
R
0
W
0
0–2
3
No function assigned. Fix to "0".
FENTRY
0: Normal read
R
W
Flash E/W enable mode entry bit
1: Program/erase enable
4–6
7
No function assigned. Fix to "0".
0
0
FEMMOD
0: Normal mode
R
W
Virtual flash emulation mode bit
1: Virtual flash emulation mode
Flash Control Register 1 (FCNT1) consists of the following two bits to control the internal flash memory.
(1) FENTRY (Flash Mode Entry) bit (Bit 3)
The FENTRY bit controls entry to flash E/W enable mode. Flash E/W enable mode can only be entered when
FENTRY = "1".
To set the FENTRY bit to "1", write "0" and then "1" to the FENTRY bit in succession while the FP pin = "high". To
clear the FENTRY bit, check to see that the FSTAT1 register FSTAT bit = "1" (ready) and then write "0" to the
FENTRY bit.
Note that the following operations cannot be performed while programming or erasing the internal flash
memory (FSTAT1 register FSTAT bit = "0" (busy)). If one of these operations is attempted, the FENTRY bit
is cleared to "0" in hardware.
1) Writing "0" to the FENTRY bit
2) Entering a low-level signal to the FP pin
3) Entering a low-level signal to the RESET# pin
When running a program resident in the internal flash memory while the FENTRY bit = "0", the EI vector entry
is located at the address H’0000 0080 of the internal flash memory. When running the flash write/erase
program in the RAM while the FENTRY bit = "1", the EI vector entry is located at the address H’0080 4000 of
the RAM, allowing the flash programming/erase operation to be controlled using interrupts.
Table 6.4.1 Changes of the EI Vector Entry by FENTRY
FENTRY
EI Vector Entry
Address
0
1
Internal flash memory area
Internal RAM area
H'0000 0080
H'0080 4000
(2) FEMMOD (Virtual Flash Emulation Mode) bit (Bit 7)
The FEMMOD bit controls entry to virtual flash emulation mode. Virtual flash emulation mode is entered by
setting the FEMMOD bit to "1" while the FENTRY bit = "0". (For details, see Section 6.6, “Virtual Flash
Emulation Function.”)
32180 Group User’s Manual (Rev.1.0)
6-7
RENESAS [ RENESAS TECHNOLOGY CORP ]
