Compatibililty atmega328p with atmega169pv

I am working on a project (just ordered the board). The BOM lists

digikey has it; but it’s 7.50, about twice that of atmega328p… While the 328 is a 10mhz version, the 169 is 8mhz; not sure if that’s a problem, as we can run the 328 at 8mhz… It looks like the pin outs are the same, but I left my glasses in the car so I could be wrong.

The 169 is listed as a CMOS version; for whatever that’s worth – are there any reasons to not use a 328?

Lots of IO on that ATmega169pv so presumably the project is doing something with it. The pin map for Wiring would be a sizable exercise. An ATmega328p has 2k SRAM, but ATmega169p only has 1k, and has half the flash memory.

Pinout is not the same, the ADC is on PORTF not PORTC, TWI/I2C is on PORTE not PORTC, ICP is PORTD not PORTB (that is a point of self interest), but SPI is the same PORTB. So that would need a lot changed in the map so the Wiring functions can access them.

Dose the project need all those pins? If not then the 328 is a step up.

CMOS, it means Complementary (NMOS and PMOS), they are mostly all CMOS. Atmel had a space grade ATmegaS128 which is not CMOS (e.g. probably NMOS without any PMOS) and is immune to latchup.

It also has:- On-Chip 2-cycle Multiplier JTAG (IEEE std. 1149.1 compliant) Interface – Boundary-scan Capabilities According to the JTAG Standard – Extensive On-chip Debug Support – Programming of Flash, EEPROM, Fuses, and Lock Bits through the JTAG Interface

– 4 × 25 Segment LCD Driver – Real Time Counter with Separate Oscillator – Four PWM Channels – 8-channel, 10-bit ADC – Five Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, and Standby

– 54 Programmable I/O Lines Ultra-Low Power Consumption – Active Mode: 1 MHz, 1.8V: 330 μA 32 kHz, 1.8V: 10 μA (including Oscillator) 32 kHz, 1.8V: 25 μA (including Oscillator and LCD) – Power-down Mode: 0.1 μA at 1.8V – Power-save Mode: 0.6 μA at 1.8V (Including 32 kHz RTC)

So quite a lot of extras.

But only available in surface mount DRQFN and TQFP/QFN/MLF

The reasons to use a 169 (or 329 - they make that too, with the same memory as the 328) instead of the cheaper and more available 328, would most likely be either because you need more pins than the '328 has (the mega x9 series has twice as many pins as the x8 series - presumably they wouldn't have used a 169 if they could have used a 168 - so maybe they're using those pins) OR you need a special feature of the 169 (LCD driver? That's what makes the 169 "special") OR because the code you need has already been written for the 169, and you can't justify the porting effort (which would be some work, but likely nothing hard for a moderately experienced AVR programmer). But that's assuming you're designing the board to accommodate a 169 or 328 - it sounds like you've already ordered a board.

The 169 and 328 have a completely different pinout and package (the 169 has twice as many pins)- you definitely can't just use a 328 instead on the same physical board. Maybe you were looking at the 168? There is a 168 that is pin compatible with the 328. But the 169 is a different beast.

Thanks; clearly I missed a lot w/o my glasses. No it doesn't need the all the pins, actually only needs a few (3 or 4). The cost of the chip was why I wanted to use a different chip (8 vs 9) I'll see if I can get the design files to change pins used. thank you

daveyjones: No it doesn't need the all the pins, actually only needs a few (3 or 4).

The 169 is a bizzaro choice for such a use case then!

The 169 was the chip on the atmel butterfly eval board, which was one of the relatively easily accessible boards for hobbyists BEFORE arduino. …