CrossRoads:
The currently available datasheets from last summer show 2 UARTs for '644A and '644PAATmega164A/PA/324A/PA/644A/PA/1284/P Summary
(file size: 595899, 33 pages, revision C, updated: 06/2011)
http://www.atmel.com/Images/8272S.pdfATmega164A/PA/324A/PA/644A/PA/1284/P Complete
(file size: 24554094, 584 pages, revision C, updated: 06/2011)
http://www.atmel.com/Images/doc8272.pdfI didn't look into these:
ATmega164P, ATmega324P, ATmega644P Automotive Complete
(file size: 6188428, 377 pages, revision F, updated: 09/2009)
http://www.atmel.com/Images/doc7674.pdfATmega164P/324P/644P Complete
(file size: 9613207, 439 pages, revision 0, updated: 07/2010)
http://www.atmel.com/Images/doc8011.pdfATmega164P/324P/644P Summary
(file size: 565743, 28 pages, revision O, updated: 01/2010)
http://www.atmel.com/Images/8011S.pdf
But there does exist a ATmega 644/V chip, which datasheet I posted before.
From cover sheet:
• Peripheral Features
– Two 8-bit Timer/Counters with Separate Prescalers and Compare Modes
– One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture
Mode
– Real Time Counter with Separate Oscillator
– Six PWM Channels
– 8-channel, 10-bit ADC
Differential mode with selectable gain at 1x, 10x or 200x
– Byte-oriented Two-wire Serial Interface
– One Programmable Serial USART– Master/Slave SPI Serial Interface
– Programmable Watchdog Timer with Separate On-chip Oscillator
– On-chip Analog Comparator
– Interrupt and Wake-up on Pin Change
Lefty