Rainbow Electronics ATmega163L - Manual (Page 134)

ATmega163(L)
134
positive pulse and issue a new Programming Enable command. If the $53 is not seen within 32 attempts, there is no
functional device connected.
4. If a chip erase is performed (must be done to erase the Flash), wait 2•t
WD_FLASH
after the instruction, give RESET a
positive pulse, and start over from Step 2. See Table 59 for the t
WD_FLASH
figure.
5. The Flash is programmed one page at a time. The memory page is loaded one byte at a time by supplying the 6
LSB of the address and data together with the Load Program Memory Page instruction. The Program Memory Page
is stored by loading the Write Program Memory Page instruction with the 7 MSB of the address. If polling is not
used, the user must wait at least t
WD_FLASH
before issuing the next page. (Please refer to Table 59). Accessing the
serial programming interface before the Flash write operation completes can result in incorrect programming.
6. The EEPROM array is programmed one byte at a time by supplying the address and data together with the appro-
priate Write instruction. An EEPROM memory location is first automatically erased before new data is written. If
polling is not used, the user must wait at least t
WD_EEPROM
before issuing the next byte. (Please refer to Table 59). In
a chip erased device, no $FFs in the data file(s) need to be programmed.
7. Any memory location can be verified by using the Read instruction which returns the content at the selected
address at serial output MISO/PB6.
8. At the end of the programming session, RESET can be set high to commence normal operation.
9. Power-off sequence (if needed):
Set XTAL1 to ‘0’ (if a crystal is not used).
Set RESET to ‘1’.
Turn V
CC
power-off
Data Polling Flash
When a page is being programmed into the Flash, reading an address location within the page being programmed will give
the value $FF. At the time the device is ready for a new page, the programmed value will read correctly. This is used to
determine when the next page can be written. Note that the entire page is written simultaneously and any address within
the page can be used for polling. Data polling of the Flash will not work for the value $FF, so when programming this value,
the user will have to wait for at least t
WD_FLASH
before programming the next page. As a chip-erased device contains $FF in
all locations, programming of addresses that are meant to contain $FF, can be skipped. See Table 59 for t
WD_FLASH
value.
Data Polling EEPROM
When a new byte has been written and is being programmed into EEPROM, reading the address location being pro-
grammed will give the value $FF. At the time the device is ready for a new byte, the programmed value will read correctly.
This is used to determine when the next byte can be written. This will not work for the value $FF, but the user should have
the following in mind: As a chip-erased device contains $FF in all locations, programming of addresses that are meant to
contain $FF, can be skipped. This does not apply if the EEPROM is re-programmed without chip-erasing the device. In this
case, data polling cannot be used for the value $FF, and the user will have to wait at least t
WD_EEPROM
before programming
the next byte. See Table 59 for t
WD_EEPROM
value.
Programming Times for Non-Volatile Memory
The internal RC oscillator is used to control programming time when programming or erasing Flash, EEPORM, fuses, and
lock bits. During parallel or serial programming, the device is in reset, and this oscillator runs at its initial, uncalibrated fre-
quency, which may vary from 0.5 MHz to 1.0 MHz. In software it is possible to calibrate this oscillator to 1.0 MHz (see
“Calibrated Internal RC Oscillator” on page 32). Consequently, programming times will be shorter and more accurate when
programming or erasing non-volatile memory from software, using SPM or the EEPROM interface. See Table 59 for a sum-
mary of programming times.