st92f120 STMicroelectronics, st92f120 Datasheet - Page 44

• Manufacturer Part Number: st92f120
• Description: 8/16-bit Flash Mcu Family With Ram, Eeprom And J1850 Blpd
• Manufacturer: STMicroelectronics

ST92F120 - SINGLE VOLTAGE FLASH & EEPROM
REGISTER DESCRIPTION (Cont’d)
Bit 2 = WFIS: Wait For Interrupt Status.
If this bit is reset, the WFI instruction puts the
Flash macrocell in Stand-by mode (immediate
read possible, but higher consumption: 100 A); if
it is set, the WFI instruction puts the Flash macro-
cell in Power-Down mode (recovery time of 10 s
needed before reading, but lower consumption:
10 A). The Stand-by mode or the Power-Down
mode will be entered only at the end of any current
Flash or EEPROM write operation.
In the same way following an HALT or a STOP in-
struction, the Memory enters Power-Down mode
only after the completion of any current write oper-
ation.
0: Flash in Standby mode on WFI
1: Flash in Power-Down mode on WFI
Note: HALT or STOP mode can be exited without
problems, but the user should take care when ex-
iting WFI Power Down mode. If WFIS is set, the
user code must reset the XT_DIV16 bit in the
R242 register (page 55) before executing the WFI
instruction. When exiting WFI mode, this gives the
Flash enough time to wake up before the interrupt
vector fetch.
Bit 1 = FEIEN: Flash & EEPROM Interrupt enable .
This bit selects the source of interrupt channel
INTx between the external interrupt pin and the
Flash/EEPROM End of Write interrupt. Refer to
the Interrupt chapter for the channel number.
0: External interrupt enabled
1: Flash & EEPROM Interrupt enabled
44/324
9
Bit 0 = EBUSY: EEPROM Busy (Read Only).
This bit is automatically set during a Page Update
operation when the first address to be modified is
latched in the EEPROM memory, or during Chip
Erase operation when bit EWMS is set. At the end
of the write operation or during a Sector Erase
Suspend this bit is automatically reset and the
memory returns to read mode. When this bit is set
every read access to the EEPROM memory will
output invalid data (FFh equivalent to a NOP in-
struction), while every write access to the EEP-
ROM memory will be ignored. At the end of the
write operation this bit is automatically reset and
the memory returns to read mode. Bit EBUSY re-
mains high for a maximum of 10ms after Power-
Up and when exiting Power-Down mode, meaning
that the EEPROM memory is not yet ready to be
accessed.
0: EEPROM not busy
1: EEPROM busy