Recent content by ferrymanr

I need to generate a square wave on one pin of a 14M2 so I can derive a low current negative voltage rail. This needs to run continuously as a background task. Is hpwm the best option? If so am I restricred to using hpwm D (B.5) as the output? Unfortunately using B.5 makes my board layout a...

I have just programmed up an 08M2 to do a small task and it works fine. I ordered up a couple of extra 08M2 chips but those supplied are marked 08M2+. Had a good look around the PICAXE documentation but could not find an information on what is extra (or lost) with the "+" version. Can someone...

I need a very simple RS-232 monitor to sniff an RS-232 9600bd line and wait for an ASCII "W" then store the next 7 bytes for a simple calculation and the turn an output off or on. The 08M2 should be more than enough to do this but not sure how to use serin with a qualifier to get the next 7...

I have an unusual GaAs RF switch device (Macom SW-419) that requires negative logic drive of -6V to 0V. As the switching needs to be fairly fast (ideally <<20nS) the opto isolators I have tried seem to be too slow. I even considered running the PICAXE with 0V supply and -5V ground but then the...

I have an application that drives two stepper motors and responds to various commands via hserin. The serial comms needs to run in background to avoid too much interrruption of the stepper drive. Until now I have been receiving a fixed length command string consisting of command letter or...

My external device defaults to parallel mode and requires a sequence of pulses to initialise serial mode. To get the sequence I need to send a single pulse on the hspi clock line (C.3). I can't use the hspiout command as it works in byte mode that will send 8 pulses. Is there any problem with...

In previous projects I have manged to do multiplication and division wiith 31bit numbers as described elsewhere on this site. However I now have a requirement to calculate the data string required to be sent via SPI to a DDS synthesiser. The frequency control data is a 32 bit string (4 bytes)...

I transferred my code from 20X2 to 28X2 and got all the PWM code and math working correctly but am having problems getting my serial comms working again. I am using HSERSETUP B9600_16,%001 to run in background as before but hserptr only shows a couple of characters as being in the buffer when...

I am having a problem getting two independent and simultaneous PWM streams, each with a different duty cycle. What I am trying to do is speed and direction control of two motors from a 20X2. I am driving an external H-bridge Pwmout only permits use on C.5 and I can't see how hpwm can specify...

I have a geared DC motor rated at 24V 2A. I intend driving with PWM from a 20X2 into an L298 driver (because I have some in the box). The idea is to drive the L298 bridge inputs from the 20X2 to provide direction control and apply PWM to the L298 enable input. I can then turn on both bridge...

I have an old spectrum analyzer which outputs X and Y voltages for external display or analogue plotting together with a pen up/down signal (not GPIB data). I have in mind using a 20X2 to perform two channels of 10 bit A/D and converting to HPGL plotting commands to send out as serial data to...

I have been struggling with lost or corrupted characters using hsersetup, get characters from the scratchpad and hserout. The problem is definitely on input as debug data is wrong. Hsersetup is set for background operation. My program does not use PWM or interrupts but does use pulsout and...

I am having a small problem with the parallel drive LCD subroutines in the manual section 3 page 40. These do work with the display OK but contrary to the note at the bottom of the page the "let pins =" commands do seem to screw up outputs 0 and 1 on my 18M and I would like to use them...

I have a need to analyse and debug my PICAXE project anbd have looked at PC based logic analysers. Two that I have found are the Saleae and USBee AX Pro. Can anyone comment on these or suggest any alternatives that I might have missed. Are there any real disadvantages to the PC based (hence...

I am currently using an L297 to drive an L298 with some success but do not need quite so much power capability. It seems the L293E will handle 1A at 24V but has much better quiescent current, is cheaper than the L298 and is a standard DIL layout. I will still need an L297 for control to save a...