The MCS USBISP programmer is a new USB programmer based on the FT232RL chip.

The FT232RL is a well known virtual COM port chip. It can also be used in so called 'bitbang' mode. Exactly this mode is used.

 

The programmer is based on the Sample ELectronics SE-UTS cable. It is modified (the flatcable is removed and a connector is soldered)

But you can also create your own programmer.

 

 

The circuit shows the used FT232RL chip. There are only a few connections to the target 8051 processor : RTS(CLOCK), CTS(MOSI), DTR(RESET), DSR(MISO).

GND is also connected but not shown here. VCC from the USB which is 5V is also connected. But take in mind this is a stand alone programmer.

Normally you would not conenct 5V from the USB to the target circuit since the USB can only supply little power. it is best if you enable your circuit with its own power. Also note that for ISP programming the used ISP pins may not have a load. When there is hardware connected to the circuit with a low impedance, either use some switch or a MUX.

 

TX and RX of the FTDI are not used. This way you can use the FTDI in virtual COM port mode as well to communicate with the processor.

 

The circuit above does not show the complete FT232RL setup. Only the connections for the programming are shown.

Also the 898252 requires an XTAL and capacitors. It is not shown either but your target hardware surely would have this already.

 

In order to work the FTDI drivers must be installed. On windows 10 they are installed automatically. On older platforms you might need to download from the FTDI site : https://ftdichip.com/drivers/d2xx-drivers/

 

 

In options select the programmer :

 

The SCAN button can be clicked to check the USB devices for FTDI chips. When found, their serial number is shown.

When multiple FTDI devices are connected it is important you select the proper one.

If you have one device you can also leave the serial number blank.

 

The programmer has the usual options :

 

 

You can erase the chip, read and write it.

Identify will not work for the 898252.

 

Programming is relatively slow in ISP mode.

Parallel mode is much faster but does not work in circuit.