AT90PWM2B-16SE ATMEL [ATMEL Corporation], AT90PWM2B-16SE Datasheet - Page 294

• Manufacturer Part Number: AT90PWM2B-16SE
• Description: 8-bit Microcontroller with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

25.9.1
294
AT90PWM2/3/2B/3B
Serial Programming Algorithm
Figure 25-10. Serial Programming and Verify
Notes:
When programming the EEPROM, an auto-erase cycle is built into the self-timed programming
operation (in the Serial mode ONLY) and there is no need to first execute the Chip Erase
instruction. The Chip Erase operation turns the content of every memory location in both the
Program and EEPROM arrays into 0xFF.
Depending on CKSEL Fuses, a valid clock must be present. The minimum low and high periods
for the serial clock (SCK) input are defined as follows:
Low:> 2 CPU clock cycles for f
High:> 2 CPU clock cycles for f
When writing serial data to the AT90PWM2/2B/3/3B, data is clocked on the rising edge of SCK.
When reading data from the AT90PWM2/2B/3/3B, data is clocked on the falling edge of SCK.
See
To program and verify the AT90PWM2/2B/3/3B in the serial programming mode, the following
sequence is recommended (See four byte instruction formats in
1. Power-up sequence:
2. Wait for at least 20 ms and enable serial programming by sending the Programming
3. The serial programming instructions will not work if the communication is out of synchro-
4. The Flash is programmed one page at a time. The memory page is loaded one byte at a
Apply power between V
tems, the programmer can not guarantee that SCK is held low during power-up. In this
case, RESET must be given a positive pulse of at least two CPU clock cycles duration
after SCK has been set to “0”.
Enable serial instruction to pin MOSI.
nization. When in sync. the second byte (0x53), will echo back when issuing the third
byte of the Programming Enable instruction. Whether the echo is correct or not, all four
bytes of the instruction must be transmitted. If the 0x53 did not echo back, give RESET a
positive pulse and issue a new Programming Enable command.
time by supplying the 6 LSB of the address and data together with the Load Program
Figure 25-11
1. If the device is clocked by the internal Oscillator, it is no need to connect a clock source to the
2. V
XTAL1 pin.
CC
- 0.3V < AVCC < V
for timing details.
CC
MOSI_A
MISO_A
SCK_A
ck
and GND while RESET and SCK are set to “0”. In some sys-
ck
CC
< 12 MHz, 3 CPU clock cycles for f
< 12 MHz, 3 CPU clock cycles for f
+ 0.3V, however, AVCC should always be within 1.8 - 5.5V
XTAL1
RESET
GND
(1)
AVCC
VCC
+1.8 - 5.5V
+1.8 - 5.5V
Table
(2)
ck
ck
>= 12 MHz
>= 12 MHz
25-16):
4317J–AVR–08/10