Wiki Techno-Innov - Contributions [fr]

Utilisateur:Cyprien

2020-09-03T00:49:48Z

Cyprien :

== FTDI Basic auto-reset for LPC ==

[[Image:CyprienARSchemat.png|right]]

LPC micro-controlers can be programmed using the standard serial line using the ISP mode. This requires to have the <code>ISP</code> pin grounded when the LPC goes out of reset. It's often done using two micro-switches you have to manually press and release in the correct order.

As I am using the [https://www.sparkfun.com/products/9873 FTDI Basic module from Sparkfun] to connect to the serial line, I made this circuit to use the <code>DTR</code> modem signal to easily reset and enter ISP mode.

[[Image:FTDIBasic.jpg|200x200px|center]]

How does it work?
* When the <code>DTR</code> signal goes up, the <code>Reset</code> is pulled down, putting the LPC into reset. At this moment C1 starts to discharge through R3, and if <code>DTR</code> is asserted long enough, the <code>ISP</code> pin is put low too.
* When <code>DTR</code> is back to normal, the LPC goes out of <code>Reset</code>, and if C1 is discharged enough enters <code>ISP</code> mode.

I used 2200 ohm for R3 and 47uF for C1 (which I had close), which gives a RC time of about 100ms. Note that a smaller capacitor can be used, as soon as R3 value is adapted. In my experience a 100ms <code>DTR</code> signal is enough to trigger both Reset and ISP mode, whereas a 10ms signal just triggers Reset. This is perfect!

Cons: if you want to manually push the reset button, disconnect the ISP pin as it will likely be triggered.

Here's a picture of the circuit soldered on a Vero Board (compact, some holes hold two pins together) and connected to the [[Products/DTPlug|DTPlug]] :

[[Image:CyprienARPhoto.jpg|535x400px|center]]

== Next Hack ==

Fichier:CyprienARPhoto.jpg

2020-09-03T00:49:09Z

Cyprien :

Fichier:FTDIBasic.jpg

2020-09-03T00:48:54Z

Cyprien :

Fichier:CyprienARSchemat.png

2020-09-03T00:48:43Z

Cyprien :

Utilisateur:Cyprien

2020-09-03T00:47:28Z

Cyprien :

Utilisateur:Cyprien

2020-09-03T00:36:01Z

Cyprien :

== FTDI Basic auto-reset for LPC ==

[[Image:CyprienARSchemat.png|right]]

LPC micro-controlers can be programmed using the standard serial line using the ISP mode. This requires to have the <code>ISP</code> pin grounded when the LPC goes out of reset. It's often done using two micro-switches you have to manually press and release in the correct order.

As I am using the FTDI Basic module from Sparkfun to connect to the serial line, I made this circuit to use the <code>DTR</code> modem signal to easily reset and enter ISP mode.

[[Image:FTDIBasic.jpg|200x200px|center]]

How does it work?
* When the <code>DTR</code> signal goes up, the <code>Reset</code> is pulled down, putting the LPC into reset. At this moment C1 starts to discharge through R3, and if <code>DTR</code> is asserted long enough, the <code>ISP</code> pin is put low too.
* When <code>DTR</code> is back to normal, the LPC goes out of <code>Reset</code>, and if C1 is discharged enough enters <code>ISP</code> mode.

I used 2200 ohm for R3 and 47uF for C1 (which I had close), which gives a RC time of about 100ms. Note that a smaller capacitor can be used, as soon as R3 value is adapted. In my experience a 100ms <code>DTR</code> signal is enough to trigger both Reset and ISP mode, whereas a 10ms signal just triggers Reset. This is perfect!

Cons: if you want to manually push the reset button, disconnect the ISP pin as it will likely be triggered.

Here's a picture of the circuit soldered on a Vero Board (compact, some holes hold two pins together) and connected to the [[Products/DTPlug|DTPlug]] :

[[Image:CyprienARPhoto.jpg|535x400px|center]]

Utilisateur:Cyprien

2020-09-03T00:35:23Z

Cyprien :

== FTDI Basic auto-reset for LPC ==

[[Image:CyprienARSchemat.png|right]]

LPC micro-controlers can be programmed using the standard serial line using the ISP mode. This requires to have the <code>ISP</code> pin grounded when the LPC goes out of reset. It's often done using two micro-switches you have to manually press and release in the correct order.

[[Image:FTDIBasic.jpg|200x200px|center]]

How does it work?
* When the <code>DTR</code> signal goes up, the <code>Reset</code> is pulled down, putting the LPC into reset. At this moment C1 starts to discharge through R3, and if <code>DTR</code> is asserted long enough, the <code>ISP</code> pin is put low too.
* When <code>DTR</code> is back to normal, the LPC goes out of <code>Reset</code>, and if C1 is discharged enough enters <code>ISP</code> mode.

I used 2200 ohm for R3 and 47uF for C1 (which I had close), which gives a RC time of about 100ms. Note that a smaller capacitor can be used, as soon as R3 value is adapted. In my experience a 100ms <code>DTR</code> signal is enough to trigger both Reset and ISP mode, whereas a 10ms signal just triggers Reset. This is perfect!

Cons: if you want to manually push the reset button, disconnect the ISP pin as it will likely be triggered.

Here's a picture of the circuit soldered on a Vero Board (compact, some holes hold two pins together) and connected to the [[Products/DTPlug|DTPlug]] :

[[Image:CyprienARPhoto.jpg|535x400px|center]]

Utilisateur:Cyprien

2020-09-03T00:32:54Z

Cyprien :

Utilisateur:Cyprien

2020-09-03T00:30:19Z

Cyprien :

Utilisateur:Cyprien

2020-09-03T00:29:58Z

Cyprien :

== FTDI Basic auto-reset for LPC ==

LPC micro-controlers can be programmed using the standard serial line using the ISP mode. This requires to have the <code>ISP</code> pin grounded when the LPC goes out of reset. It's often done using two micro-switches you have to manually press and release in the correct order.

Utilisateur:Cyprien

2020-09-03T00:28:07Z

Cyprien : Page blanchie

Utilisateur:Cyprien

2020-09-03T00:19:57Z

Cyprien :

Test