Introduction
The C505A is an enhanced, upgraded version of the C505-2R eight bit microcontroller and incorporates more on-chip RAM, a 10-bit A/D Converter and 32K bytes of on-chip OTP memory. With a maximum external clock rate of 20 MHz, the C505A has an instruction cycle time of 300 ns.
With the C505A-4E fast OTP programming cycles are achieved (1 byte in 100 µsec). Also several levels of OTP memory protection can be selected. The basic functionality of the C505A-4E as a microcontroller is identical to the C505A-L (romless part) functionality. Therefore, the programmable C505A-4E typically can be used for prototype system design.

Listed below is a summary of the main features of the C505A family:
• Fully compatible to standard 8051 microcontroller
• Superset of the 8051 architecture with 8 datapointers
• Up to 20 MHz operating frequency
   – 375 ns instruction cycle time @ 16 MHz
   – 300 ns instruction cycle time @ 20 MHz (50 % duty cycle)
• 32K byte on-chip OTP memory
   – C505A-4E : programmable OTP versions
   – C505A-L : without on-chip program memory
   – alternatively up to 64 K bytes of external program memory
• 256 byte on-chip RAM
• 1 K byte on-chip XRAM
• Five ports: 32 + 2 digital I/O lines(Port 1 with mixed analog/digital I/O capability)
• Three 16-bit timers/counters
   – Timer 0 / 1 (C501 compatible)
   – Timer 2 with 4 channels for 16-bit capture/compare operation
• Full CAN Module (C505CA only)
   – 256 register/data bytes located in external data memory area
   – 1 MBaud CAN baudrate when operating frequency is equal to or above 8 MHz
   – internal CAN clock prescaler when input frequency is over 10 MHz
• Full duplex serial interface with programmable baudrate generator (USART)
• 10-bit A/D Converter with 8 multiplexed inputs
   – Built-in self calibration
• Twelve interrupt sources with four priority levels
• On-chip emulation support logic
   –Enhanced Hooks Technology TM 1)
• Programmable 15-bit Watchdog Timer
• Oscillator Watchdog
• Fast Power On Reset
• Power Saving Modes
   – Slow-down mode
   – Idle mode (can be combined with slow-down mode)
   – Software power-down mode with wake up capability through P3.2/INT0 or P4.1/RXDC pin
• P-MQFP-44 package
• Pin configuration is compatible to C501, C504, C511/C513-family, C505, C505C
• Temperature ranges:
   SAB-C505A versions TA = 0 to 70 °C
   SAF-C505A versions TA = – 40 to 85°C
   SAH-C505A versions TA = – 40 to 110°C (max. operating frequency: TBD)
   SAK-C505A versions TA = –40 to 125°C (max. operating frequency: 12 MHz
                                                                                           with 50 % duty cycle)