Can Someone Give Context to These Pin Connections? - Page 1
Forum section: electronics / beginners

author: Max Holdcroft
author_rank: Contributor
timestamp: May 24, 2024, 09:42:49 am
content: I'm looking at the schematic for the ISP_BLE_DS1507 (https://www.insightsip.com/fichiers_insightsip/pdf/ble/ISP1507/isp_ble_DS1507.pdf), specifically the reference designs page, and I'm a little confused as to what these pins mean. Why are OUT_ANT and OUT_MOD connected? Presumably OUT_ANT is antenna, but what does OUT_MOD mean? The pin description has it listed as RF ourput (I guess a typo for output)? Is this the output signal for the internal antenna? What are SWDCLK and SWDIO-nRESET? The pin description page doesn't offer much info as to what they actually do.Thank you for anyone who can help me!Max

author: tooki
author_rank: Super Contributor
timestamp: May 24, 2024, 10:58:25 am
content: My guess, from looking at the pin list and the module’s internal schematic, is that OUT_MOD is the actual RF output, and that OUT_ANT is actually theinputto the internal antenna. In the dev board schematics, they have the ability to cut the trace between those pads, and instead jumper them together to an SMA jack for “RF testing”.It’s hard to be sure since their module’s internal schematic is incomplete.Not that this question has any relevance to you: you bridge those pads like they tell you to and call it a day.SWDCLK and SWDIO are the Serial Wire Debug interface, the clock and IO lines, respectively. Just like the datasheet says. What’s stopping you from googling to find out what SWD is?

author: Max Holdcroft
author_rank: Contributor
timestamp: May 24, 2024, 11:13:39 am
content: Quote from: tooki on May 24, 2024, 10:58:25 amHey man,Thank you so much for your response. It's not so much figuring out what SWD stands for that's the issue; I'm trying to figure out what the pins actually practically do.Thanks,Max

author: ataradov
author_rank: Super Contributor
timestamp: May 24, 2024, 01:40:53 pm
content: They are debug and programming pins.There is no chance you can brute force your way though understanding this. You need to start with basics and move your way up to more complicated stuff.

author: Max Holdcroft
author_rank: Contributor
timestamp: May 25, 2024, 02:58:18 am
content: Quote from: ataradov on May 24, 2024, 01:40:53 pmHey Alex,Thanks for your answer! So are they just for connecting to the development board and for flashing the chip or do they serve some other purpose in the circuit. Is there any reason I would actually need them beyond just uploading my program to the board?Thanks,Max

author: ataradov
author_rank: Super Contributor
timestamp: May 25, 2024, 03:27:31 am
content: Quote from: Max Holdcroft on May 25, 2024, 02:58:18 amIs uploading the program not enough of a reason?No, they don't serve any other reason, but the one they do serve is sort of important on its own.

author: Max Holdcroft
author_rank: Contributor
timestamp: May 25, 2024, 03:49:06 am
content: Quote from: ataradov on May 25, 2024, 03:27:31 amWait I thought that the idea was that you would attach the chip to the dev board, flash the program, then disconnect the chip from the board and solder it into the PCB you're using. Is that not how you program the board? I thought that once you had done that you wouldn't need to access the SWD pins anymore.

author: ataradov
author_rank: Super Contributor
timestamp: May 25, 2024, 03:53:25 am
content: Quote from: Max Holdcroft on May 25, 2024, 03:49:06 amThis is not how MCU development works for the last 30 years.Quote from: Max Holdcroft on May 25, 2024, 03:49:06 amDo you realize how much effort the firmware development takes? How are you going to get the firmware you are going to program into the module without reprogramming it 100s of times to debug it?You solder empty modules then use debugger/programmer to place the firmware. This is true for the development boards and for the production hardware.In some cases you can order pre-programmed modules, but this usually includes purchase of 1-10k units. And it rarely makes sense. You still need to have some way t program the board. Not provisioning for that is a really bad idea.

author: Max Holdcroft
author_rank: Contributor
timestamp: May 25, 2024, 03:54:19 am
content: Quote from: ataradov on May 25, 2024, 03:53:25 amOk that makes so much more sense. Thank you!

author: radiolistener
author_rank: Super Contributor
timestamp: May 25, 2024, 07:00:02 am
content: Quote from: Max Holdcroft on May 24, 2024, 09:42:49 amThis is SWD interface which is used for programming and in-circuit code debugging.