Our Programmable Clocks are In-System Programmable using I2C protocol. However, the difference lies in programming the registers of the clocks which are Volatile as well as Non-Volatile. We had In-System Reprogrammable Clocks (now obsolete) like the CY27EE16 and CY22701 having the capability to program both the Volatile as well as Non-Volatile part of the memory In-System using I2C protocol, without using any external hardware programmer, though it can be used. The Non-Volatile memory registers of our Programmable Clocks like the CY22150, CY22393/4/5 etc. cannot be programmed In-System using I2C. For programming this Non-Volatile register memory, you would need to use our CY3672-USB Programmer hardware and the CyberClocks software which would generate the Jedec file for the hardware programmer. The CY3672 Software will use this jedec file to program the part with the CY3672-USB Hardware Programmer.
So, our In-System Reprogrammable clocks were completely In-System programmable using I2C while our Programmable Clocks require a hardware programmer for their Non-Volatile Register memory.