inglewoodpete
Senior Member
Now that I have your attention, this is not a new PICAXE model or product from Rev Ed. Rather, it is an attempt to get the most PICAXE-punch from a 14-pin-DIL-like package.
In the past I have developed several projects based on the PICAXE 14M. The 14 pin PICAXE is great for small applications. However, to get the full potential from the 11* programmable pins of the 14M, 256 bytes of available program space which also doubles as EEPROM data storage, can be severely limiting. (*12 programmable pins if SerRxd is used.)
Another idea to get a more powerful, small-footprint PICAXE was suggested here a few months ago, where part of a 20X2 was physically carved off to leave 14 pins. However, the penalty paid for this approach is that some of the 20X2's most powerful features were lost: hi2c, hSerial and hspi.
My design offers the ability to configure the module as a close-to-drop-in equivalent of the 14M. At the other end of the scale, the 14-pin module can be configured with the 20X2's hi2c and hSerial at the same time. Another configuration option allows 9 ADC channels. Not bad for 11 or 12 programmable I/O pins! It goes without saying that the 20X2 on this module can run at 64MHz, a far superior speed than 8MHz on the 14M.
The PICAXE 20X2 SMD chip is physically about 75% of the size of a 14-pin DIL package. The prototype PCB that I developed is a double-sided through-hole-plated board that measures just 22 x 15.5mm. Actually, the PCB is larger than necessary as I included an on-board 100nF decoupling capacitor and a led/330r resistor combination connected to the Serial Out/A.0 pin. In a separate project I had another PCB that was about 22mm wide fabricated in China. I added the artwork of this board to the end of the other design and the composite board was manufactured with a score line between the PCBs that allowed them to be separated easily. So for less than A$1 each, I got 25 of the prototype PCBs made. The apparent thickness of the PCB in photo #1 indicates the "package" is smaller than it first appears.
The different hardware options would usually be configured when fabricating the module by bridging 6 SPDT solder jumpers.
Q. Why would you not just use a 20X2 SMD PICAXE when designing a project?
A. Most of my work with PICAXEs is just a low budget hobby. I rarely fabricate PCBs, especially for prototypes. This 14-pin DIL module allows the development of quite sophisticated projects on stripboard("veroboard"). It also allows more flexibility and program space for my existing 14-pin PICAXE projects that have outgrown their original, humble 14M.
Peter
In the past I have developed several projects based on the PICAXE 14M. The 14 pin PICAXE is great for small applications. However, to get the full potential from the 11* programmable pins of the 14M, 256 bytes of available program space which also doubles as EEPROM data storage, can be severely limiting. (*12 programmable pins if SerRxd is used.)
Another idea to get a more powerful, small-footprint PICAXE was suggested here a few months ago, where part of a 20X2 was physically carved off to leave 14 pins. However, the penalty paid for this approach is that some of the 20X2's most powerful features were lost: hi2c, hSerial and hspi.
My design offers the ability to configure the module as a close-to-drop-in equivalent of the 14M. At the other end of the scale, the 14-pin module can be configured with the 20X2's hi2c and hSerial at the same time. Another configuration option allows 9 ADC channels. Not bad for 11 or 12 programmable I/O pins! It goes without saying that the 20X2 on this module can run at 64MHz, a far superior speed than 8MHz on the 14M.
The PICAXE 20X2 SMD chip is physically about 75% of the size of a 14-pin DIL package. The prototype PCB that I developed is a double-sided through-hole-plated board that measures just 22 x 15.5mm. Actually, the PCB is larger than necessary as I included an on-board 100nF decoupling capacitor and a led/330r resistor combination connected to the Serial Out/A.0 pin. In a separate project I had another PCB that was about 22mm wide fabricated in China. I added the artwork of this board to the end of the other design and the composite board was manufactured with a score line between the PCBs that allowed them to be separated easily. So for less than A$1 each, I got 25 of the prototype PCBs made. The apparent thickness of the PCB in photo #1 indicates the "package" is smaller than it first appears.
The different hardware options would usually be configured when fabricating the module by bridging 6 SPDT solder jumpers.
Q. Why would you not just use a 20X2 SMD PICAXE when designing a project?
A. Most of my work with PICAXEs is just a low budget hobby. I rarely fabricate PCBs, especially for prototypes. This 14-pin DIL module allows the development of quite sophisticated projects on stripboard("veroboard"). It also allows more flexibility and program space for my existing 14-pin PICAXE projects that have outgrown their original, humble 14M.
Peter
Attachments
-
108.5 KB Views: 157
-
136.9 KB Views: 144
Last edited: