165 of 208
ZBasic Language Reference 157 ZX Microcontroller Family Appendix C - ZX-24 Series Hardware Reference The ZX-24 series devices comprise an Atmel AVR ATmega microcontroller along with some support circuitry on a 24-pin module that is simple to connect for operation. The primary difference between the members of the ZX-24 series devices is specific ATmega or Atxmega microcontroller used and the amount of RAM, EEPROM and Program Memory available for use by your programs. The table below summarizes the differences. ZX-24 Series Devices Device AVR Microcontroller Mode RAM Persistent Memory Program Memory Operating Voltage ZX-24 ATmega32 VM 1536 992 32K 3.6-5.5V ZX-24a ATmega644 VM 3584 2016 32K 3.6-5.5V ZX-24p ATmega644P VM 3584 2016 32K 3.6-5.5V ZX-24n ATmega644P Native 4096 2016 62K 3.6-5.5V ZX-24r ATmega1284P VM 15744 4064 60K 3.6-5.5V ZX-24s ATmega1284P Native 16384 4064 124K 3.6-5.5V ZX-24x ATxmega32A4 Native 4096 1024 32K 2.6-3.6V The ZX-24 series devices have other resources available to your program including a high-speed serial port, analog-to-digital converters, timers and other sub-systems that may be accessed using routines in the ZBasic System Library. Alternately, some of the resources may be accessed directly using built-in registers. See Section 3.8.1 for more information on this topic. C.1 External Connections The ZX-24 series devices can be hooked up in several different ways depending on your requirements. The simplest method is depicted below. The connector on the left is the serial connection to your PC for downloading code and transmitting/receiving data on serial channel 1. The connection to pin 3 of the ZX-24 series is only needed for downloading. You may wish to add a jumper in that line so that it may be disconnected for “normal” operation. Some operating systems, notably Windows XP, toggle the DTR line (pin 4 of the DB-9) on the serial ports during boot up. This will cause the ZX to reset on every positive- going transition of the DTR line. Simple ZX-24 Series Interconnection