ATMEGA164A-PU Atmel, ATMEGA164A-PU Datasheet - Page 284

IC MCU AVR 16K 20MHZ 40PDIP

ATMEGA164A-PU

Manufacturer Part Number
ATMEGA164A-PU
Description
IC MCU AVR 16K 20MHZ 40PDIP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA164A-PU

Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
32
Program Memory Size
16KB (8K x 16)
Program Memory Type
FLASH
Eeprom Size
512 x 8
Ram Size
1K x 8
Voltage - Supply (vcc/vdd)
1.8 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
40-DIP (0.600", 15.24mm)
Controller Family/series
Atmega
No. Of I/o's
32
Eeprom Memory Size
512Byte
Ram Memory Size
1KB
Cpu Speed
20MHz
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
25.8.3
25.8.4
25.8.5
25.8.6
25.8.7
8272A–AVR–01/10
Performing a Page Write
Using the SPM Interrupt
Consideration While Updating BLS
Prevent Reading the RWW Section During Self-Programming
Setting the Boot Loader Lock Bits by SPM
To execute Page Write, set up the address in the Z-pointer, write “X0000101” to SPMCSR and
execute SPM within four clock cycles after writing SPMCSR. The data in R1 and R0 is ignored.
The page address must be written to PCPAGE. Other bits in the Z-pointer must be written to
zero during this operation.
• Page Write to the RWW section: The NRWW section can be read during the Page Write.
• Page Write to the NRWW section: The CPU is halted during the operation.
If the SPM interrupt is enabled, the SPM interrupt will generate a constant interrupt when the
SPMEN bit in SPMCSR is cleared. This means that the interrupt can be used instead of polling
the SPMCSR Register in software. When using the SPM interrupt, the Interrupt Vectors should
be moved to the BLS section to avoid that an interrupt is accessing the RWW section when it is
blocked for reading. How to move the interrupts is described in
Special care must be taken if the user allows the Boot Loader section to be updated by leaving
Boot Lock bit11 unprogrammed. An accidental write to the Boot Loader itself can corrupt the
entire Boot Loader, and further software updates might be impossible. If it is not necessary to
change the Boot Loader software itself, it is recommended to program the Boot Lock bit11 to
protect the Boot Loader software from any internal software changes.
During Self-Programming (either Page Erase or Page Write), the RWW section is always
blocked for reading. The user software itself must prevent that this section is addressed during
the self programming operation. The RWWSB in the SPMCSR will be set as long as the RWW
section is busy. During Self-Programming the Interrupt Vector table should be moved to the BLS
as described in
the RWW section after the programming is completed, the user software must clear the
RWWSB by writing the RWWSRE. See
page 287
To set the Boot Loader Lock bits and general lock bits, write the desired data to R0, write
“X0001001” to SPMCSR and execute SPM within four clock cycles after writing SPMCSR.
See
Flash access.
If bits 5..0 in R0 are cleared (zero), the corresponding Boot Lock bit will be programmed if an
SPM instruction is executed within four cycles after BLBSET and SPMEN are set in SPMCSR.
The Z-pointer is don’t care during this operation, but for future compatibility it is recommended to
load the Z-pointer with 0x0001 (same as used for reading the lO
is also recommended to set bits 7 and 6 in R0 to “1” when writing the Lock bits. When program-
ming the Lock bits the entire Flash can be read during the operation.
164A/164PA/324A/324PA/644A/644PA/1284/1284P
Bit
R0
Table 25-2
for an example.
”Interrupts” on page
and
7
1
Table 25-3
6
1
for how the different settings of the Boot Loader bits affect the
BLB12
5
62, or the interrupts must be disabled. Before addressing
”Simple Assembly Code Example for a Boot Loader” on
BLB11
4
BLB02
3
BLB01
”Interrupts” on page
2
ck
bits). For future compatibility it
LB2
1
LB1
0
62.
284

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