Shield base & Serial driver question

[Natalie Wilkie]

Hi All,


Can someone please explain the main differences/benefits between the AXE020 – 28 pin project board and the AXE401 - 28X2 Shield Base board?


Also, what is the best to use with a LCD or OLED? The FMR010 serial chip or the 18m2 based AXE132 Serial OLED/LCD driver board? I know I need to make a board to mount the FRM010 on. Are there any differences in operating the two chips when they are connected to a display?

Thanks
Nat.

 

[JimPerry]

Also, what is the best to use with a LCD or OLED? The FMR010 serial chip or the 18m2 based AXE132 Serial OLED/LCD driver board? I know I need to make a board to mount the FRM010 on. Are there any differences in operating the two chips when they are connected to a display?

http://www.picaxeforum.co.uk/showthread.php?22014-Squeezing-functionality-out-of-an-OLED-display&highlight=squeezing shows how versatile the 18M2 board is - much more flexible than the FMR010 chip

 

[nick12ab]

Can someone please explain the main differences/benefits between the AXE020 – 28 pin project board and the AXE401 - 28X2 Shield Base board?

The AXE401 allows you to use Arduino shields with PICAXE by just plugging them directly in like on Arduino.

Beware that the AXE401 datasheet is highly misleading and some of the statistics are chosen in favour of PICAXE with the most atrocious being clock speed (due to PICAXE having frequency divider and interpreter and this is not taken into account for). However many shields won't work with PICAXE because PICAXE is much slower than Arduino.

I am going to go on about that speed thing because I think it is just awful. Rev-Ed put:

PICAXE: 32KHz-64MHz
Arduino: 16MHz

What would be fairer:

PICAXE: 20Hz-250KHz (but consumes just as much power as 8Khz-16MHz)
Arduino: 20MHz

The chip used by Arduino is rated for 20MHz, however a different bootloader must be programmed to program at 20MHz.

Rev-Ed could at least put:

PICAXE: 8KHz-16MHz
Arduino: 20MHz

 

[hippy]

Beware that the AXE401 datasheet is highly misleading and some of the statistics are chosen in favour of PICAXE

I don't think that's at all fair but without specifics it is difficult to counter.

On clock speed; the official Ardunio documentation describes it as 16MHz which is where that figure came from. As to what the real life execution speed is one cannot simply take into account any PICAXE overheads but not do the same for the thing being compared with.

 

[nick12ab]

On clock speed; the official Ardunio documentation describes it as 16MHz which is where that figure came from. As to what the real life execution speed is one cannot simply take into account any PICAXE overheads but not do the same for the thing being compared with.

Arduino executes compiled code and a reset is required if you want to download a program (sketch) so there's no overheads from checking for a download or anything else whilst the user code is running.

However it is Rev-Ed's documentation and they can say what they want in it.

 

[hippy]

Can someone please explain the main differences/benefits between the AXE020 – 28 pin project board and the AXE401 - 28X2 Shield Base board?

It's a bit of a difficult question to answer quickly on the differences and even harder to describe the benefits of each; it really depends on what you want to do as to which is best and it is likely both are best for different things.

It's a bit like asking about the differences/benefits of a car and truck which each use the same engine.

The AXE020 has the ability to add a ULN Darlington Driver and a L293D motor driver on the board, while the AXE401 has the ability to add on-board Eeprom, has supply regulators on-board and is designed to allow Shields to easily connected to it.

 

[jinx]

what i like about the shield is it got the header that lets you program a raw pic with the pickit 2/3 when you ready to move on from the picaxe basic, go for the OLED there are simply brill easy too see in poor light,"the future bright the future is OLED".

 

[hippy]

Arduino executes compiled code and a reset is required if you want to download a program (sketch) so there's no overheads from checking for a download or anything else whilst the user code is running.

What I meant were the overheads in using library code in creating the executable code. A compiled "C" program will almost never execute at the same Commands Per Second rate as the Instruction Per Seconds rating or at the frequency of the system clock.

There's always some overhead in a command being turned into a sequence of executed instructions whether that's done by an interpreter or the compiler and the overheads in real world compiled programs can often be higher than anticipated, the gains from compilation far less than expected.

For example, if a 16-bit x 16-bit multiplication takes 1,000 assembler instructions to perform it will have to execute those 1,000 instructions whether within interpreter firmware or in the compiled code and in both cases those instructions are executed at the system clock speeds, so there is no difference in time taken for either.

There are additional overheads associated with interpretation, particularly in obtaining the values to use, but in our multiplication example, if an interpreter takes 100 instructions to obtain those and the compiled code just 10, it may look like a 10 fold gain but the actual instructions executed are 1100 for the interpreter, 1010 for the compiler, not as much gain at all.

Of course, it depends on the balance between getting values and the execution of the function that processes those values and some cases fare better than others but it very much depends on what the program is doing.

 

[inglewoodpete]

Also, what is the best to use with a LCD or OLED? The FMR010 serial chip or the 18m2 based AXE132 Serial OLED/LCD driver board? I know I need to make a board to mount the FRM010 on. Are there any differences in operating the two chips when they are connected to a display?

If you choose the AXE401 Shield, then this LCD/Keypad plug-in shield option from Deal Extreme is available to you. I have just received my second LCD Keypad Shiled from DX today. Cheap and it just plugs in to the AXE401. The hSerial pins are still available for you to use for something other than the LCD.

Peter

 

[john2051]

Hi All,

Blimy Nick, fancy slating tech on their own forum! I have done alot of work on both platforms, and in my opinion the picaxe is streets ahead for simplicity, the coding is more
natural. I actually found it annoying switching between the two, as arduino uses FOR, but no next as an example. I dont enjoy the my computers better than yours argument,
it has been following obediently since spectrum bbc and commodore days.
That is just my opinion, of someone tired of the same old arguments for last thirty years or so.

time to move on
regards john

 

[Natalie Wilkie]

Thanks for the replies.

One more question, can you use the #Sim shield command with any of the picaxe chips?


Thanks