# SCHEMATIC REVIEW for MM8108-MF15457 Halow **URL:** \ **Category:** Hardware\ **Created:** [September 5, 2026, 4:43am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990 "2026-09-05T04:43:43Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![akhil](https://avatars.discourse-cdn.com/v4/letter/a/7ab992/32.png) [@akhil](https://community.morsemicro.com/u/akhil)\ **Post date:** [September 5, 2026, 4:43am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/1 "2026-09-05T04:43:43Z")
Hello morse micro team, [pcb3-STM32.pdf](https://community.morsemicro.com/uploads/short-url/cyhVNJXTq5URgD5m1wF2hXMMWWX.pdf) (255.9 KB) [pcb3-HALOW.pdf](https://community.morsemicro.com/uploads/short-url/c3tDlxgfwxT0k96uXtOQTcUxN5K.pdf) (172.3 KB) I am using the MM8108-MF15457 halow module in my new board design. The device is interfaced through SPI. I have attached the halow schematic and would appreciate it if you could review the design and let me know if there are any issues or recommended improvements before PCB fabrication. SPICLK-PB13 SPIMOSI-PC3 SPIMISO-PC2 SPIINT-PB15 SPICS-PE1 BUSY-PE2 WAKE-PD0 Thank you for your support. ---
**Author:** ![ajudge](https://avatars.discourse-cdn.com/v4/letter/a/c2a13f/32.png) [@ajudge](https://community.morsemicro.com/u/ajudge)\ **Post date:** [September 7, 2026, 2:37am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/2 "2026-09-07T02:37:36Z")
Hey @akhil I notice you are using an STM32F407? Have you assessed the RAM and flash usage of your application? 1MB of flash and 192KB of RAM will probably work for very light applications, but as you start to do more complex activities (eg firmware upgrades, managing multiple connections, certificate chains for SSL backed connections, specific throughput requirements) you might find you will consume these RAM and flash offered by this target relatively quickly. I’d recommend prototyping the design on a nucleo first if you haven’t already 🙂 If your debugger has a spare pin. I’d recommend breaking out MM\_BUSY onto it so you can attach a logic analyser if needed. Otherwise the schematics look okay to me. Please make sure you check them against the [MM8108-MF15457 Hardware Design Guide](https://www.morsemicro.com/resources/design_packages/MM8108-MF15457_Hardware_Design_Guide.pdf) as well 🙂 as I may have missed something. ---
**Author:** ![akhil](https://avatars.discourse-cdn.com/v4/letter/a/7ab992/32.png) [@akhil](https://community.morsemicro.com/u/akhil)\ **Post date:** [September 8, 2026, 4:28am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/3 "2026-09-08T04:28:04Z")
Hi @ajudge Thank you for your review and feedback ---
**Author:** ![amaljishnuinthings7](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@amaljishnuinthings7](https://community.morsemicro.com/u/amaljishnuinthings7)\ **Post date:** [September 8, 2026, 6:58am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/4 "2026-09-08T06:58:30Z")
Sir, I have a few doubts regarding the MM8108 HaLow module: 1. Why does the MM8108 HaLow firmware need to be sent from the STM32 to the MM8108 over SPI after every MM8108 reset or power cycle? 2. For the development board I am currently using, where can I find the BUSY pin ? Is there any option to purchase a development board with only the HaLow IC/module? Also, when is the MM8108-EKH08-01-01 expected to be released? Thank you. ---
**Author:** ![ldennis](https://avatars.discourse-cdn.com/v4/letter/l/3ab097/32.png) [@ldennis](https://community.morsemicro.com/u/ldennis)\ **Post date:** [September 9, 2026, 1:53am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/5 "2026-09-09T01:53:00Z")
> [@amaljishnuinthings7](#): > > 1. Why does the MM8108 HaLow firmware need to be sent from the STM32 to the MM8108 over SPI after every MM8108 reset or power cycle? The firmware is loaded into RAM as the chip does not have internal flash. This means it needs to be loaded on boot. > [@amaljishnuinthings7](#): > > 1. For the development board I am currently using, where can I find the BUSY pin ? Is there any option to purchase a development board with only the HaLow IC/module? Which development board are you using? The EKH05? You can refer to the user guide schematic for this (the resolution isn’t great sorry) [https://morsemicro.com/resources/user\_guides/MM8108-EKH05-User-Guide.pdf](https://morsemicro.com/resources/user_guides/MM8108-EKH05-User-Guide.pdf) > [@amaljishnuinthings7](#): > > 1. Also, when is the MM8108-EKH08-01-01 expected to be released? I believe we don’t currently have a timeline for this, but will let you know if we do release it. ---
**Author:** ![amaljishnuinthings7](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@amaljishnuinthings7](https://community.morsemicro.com/u/amaljishnuinthings7)\ **Post date:** [September 9, 2026, 6:09am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/6 "2026-09-09T06:09:20Z")
> [@ldennis](#): > > Which development board are you using? The EKH05? You can refer to the user guide schematic for this (the resolution isn’t great sorry) [https://morsemicro.com/resources/user\_guides/MM8108-EKH05-User-Guide.pdf](https://morsemicro.com/resources/user_guides/MM8108-EKH05-User-Guide.pdf) Sir, 1. We are currently using the **STM32F407G-DISC1 development board** with the **MM8108-EKH05**. I have already ported the required code and am currently testing it. However, I am facing an issue during the firmware transfer, where the firmware transmission fails. 2. For testing purposes, if I use the available **MM6108-EKH08-05US-01** module and first verify that the firmware and communication are working correctly, can I later switch to the **MM8108-EKH05** HaLow IC? Thank you. ---
**Author:** ![ldennis](https://avatars.discourse-cdn.com/v4/letter/l/3ab097/32.png) [@ldennis](https://community.morsemicro.com/u/ldennis)\ **Post date:** [September 9, 2026, 7:14am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/7 "2026-09-09T07:14:47Z")
The chip firmware and driver are different, but we deliver both of those, and swapping between should be as simple as changing the `MMHAL_CHIP_TYPE` and `FW_MBIN`. The `mmhal_wlan` abstraction layer for interfacing with the chip over SPI is agnostic to the chip and shouldn’t need to change. For accessing the busy (and wake!) pin, I think your best bet is to use the test points around the chip - see here where I discussed this with another user: ["mm8108-ekh05 v2" + esp32-p4 - #2 by ldennis](https://community.morsemicro.com/t/mm8108-ekh05-v2-esp32-p4/1920/2) ---
**Author:** ![amaljishnuinthings7](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@amaljishnuinthings7](https://community.morsemicro.com/u/amaljishnuinthings7)\ **Post date:** [September 9, 2026, 9:49am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/8 "2026-09-09T09:49:33Z")
![image](https://us1.discourse-cdn.com/flex001/uploads/morsemicro/original/1X/9d4d3bdef71b279a9fbd6362979d576a280e12af.png) Could you please mention which pin is used for the **BUSY** signal? I’m unable to identify the BUSY pin from the schematic. ---
**Author:** ![ajudge](https://avatars.discourse-cdn.com/v4/letter/a/c2a13f/32.png) [@ajudge](https://community.morsemicro.com/u/ajudge)\ **Post date:** [September 10, 2026, 1:00am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/9 "2026-09-10T01:00:50Z")
Accessing the busy pin on this board will be challenging, as it has no test point available. The most accessible point will be pin 91 on the STM32U585. ---
**Author:** ![amaljishnuinthings7](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@amaljishnuinthings7](https://community.morsemicro.com/u/amaljishnuinthings7)\ **Post date:** [September 10, 2026, 5:10am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/10 "2026-09-10T05:10:37Z")
> [@ldennis](#): > > The chip firmware and driver are different, but we deliver both of those, and swapping between should be as simple as changing the `MMHAL_CHIP_TYPE` and `FW_MBIN`. > > The `mmhal_wlan` abstraction layer for interfacing with the chip over SPI is agnostic to the chip and shouldn’t need to change. Sir, Just to confirm, does this mean that the **same host-side firmware/software can support both the MM6108 and MM8108** , with only `MMHAL_CHIP_TYPE` and `FW_MBIN` needing to be changed, while the `mmhal_wlan` SPI abstraction layer remains unchanged? Can you please confirm whether this is **fully supported for both chips** , including firmware download, initialization, and normal Wi-Fi HaLow operation? ---
**Author:** ![ldennis](https://avatars.discourse-cdn.com/v4/letter/l/3ab097/32.png) [@ldennis](https://community.morsemicro.com/u/ldennis)\ **Post date:** [September 10, 2026, 7:02am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/11 "2026-09-10T07:02:56Z")
> [@amaljishnuinthings7](#): > > Just to confirm, does this mean that the **same host-side firmware/software can support both the MM6108 and MM8108** , with only `MMHAL_CHIP_TYPE` and `FW_MBIN` needing to be changed, while the `mmhal_wlan` SPI abstraction layer remains unchanged? Yes, that is correct ---
**Author:** ![amaljishnuinthings7](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@amaljishnuinthings7](https://community.morsemicro.com/u/amaljishnuinthings7)\ **Post date:** [September 11, 2026, 6:07am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/12 "2026-09-11T06:07:22Z")
Sir, I would like to clarify all the available SPI test points/pins on this board **MM6108-EKH08-05US-02**. Please confirm, especially the **BUSY** pin is available on this board **MM6108-EKH08-05US-02**? ---
**Author:** ![ldennis](https://avatars.discourse-cdn.com/v4/letter/l/3ab097/32.png) [@ldennis](https://community.morsemicro.com/u/ldennis)\ **Post date:** [September 11, 2026, 6:42am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/13 "2026-09-11T06:42:32Z")
All the needed pins are available, see here: [Morse Micro IoT SDK: mm-ekh08-u575 SPI Readme](https://morsemicro.github.io/mm-iot-sdk/framework/doc/html/MM_EKH08_U575_README.html) ---
**Author:** ![amaljishnuinthings7](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@amaljishnuinthings7](https://community.morsemicro.com/u/amaljishnuinthings7)\ **Post date:** [September 11, 2026, 7:28am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/14 "2026-09-11T07:28:13Z")
![Screenshot (289)](https://us1.discourse-cdn.com/flex001/uploads/morsemicro/original/1X/806e8aec4fff2dda607e8573ca5e224bd017cc1d.jpeg) **MM6108-EKH08-05US-02** im asking about this module for BUSY pin availability? ---
**Author:** ![ldennis](https://avatars.discourse-cdn.com/v4/letter/l/3ab097/32.png) [@ldennis](https://community.morsemicro.com/u/ldennis)\ **Post date:** [September 11, 2026, 7:43am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/15 "2026-09-11T07:43:49Z")
yes, that’s the one I linked - the pinout of the SPI EKH08 boards are all the same, and only differ by what module is loaded. ---
**Author:** ![amaljishnuinthings7](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@amaljishnuinthings7](https://community.morsemicro.com/u/amaljishnuinthings7)\ **Post date:** [October 16, 2026, 5:20am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/16 "2026-10-16T05:20:53Z")
Sir, I need the STM32 firmware code for the MM6108-EKH08-05US-02 module. Please share the source code or SDK example. @ldennis @ajudge ---
**Author:** ![amaljishnuinthings7](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@amaljishnuinthings7](https://community.morsemicro.com/u/amaljishnuinthings7)\ **Post date:** [October 17, 2026, 6:03am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/17 "2026-10-17T06:03:02Z")
#### I’m currently using the MM8108-EKH19 Wi-Fi HaLow Evaluation Kit as an access point and have an MM6108-EKH08 Evaluation Kit. Can I connect the MM6108 kit to the MM8108 access point? @denny @ldennis @ajudge ---
**Author:** ![ajudge](https://avatars.discourse-cdn.com/v4/letter/a/c2a13f/32.png) [@ajudge](https://community.morsemicro.com/u/ajudge)\ **Post date:** [October 19, 2026, 4:51am UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/18 "2026-10-19T04:51:57Z")
> [@amaljishnuinthings7](#): > > I’m currently using the MM8108-EKH19 Wi-Fi HaLow Evaluation Kit as an access point and have an MM6108-EKH08 Evaluation Kit. Can I connect the MM6108 kit to the MM8108 access point? Yes > [@amaljishnuinthings7](#): > > I need the STM32 firmware code for the MM6108-EKH08-05US-02 module. Please share the source code or SDK example. You can find the SDK for the EKH08 here: [GitHub - MorseMicro/mm-iot-sdk · GitHub](https://github.com/MorseMicro/mm-iot-sdk/) with documentation available at [Morse Micro IoT SDK: Introduction](https://morsemicro.github.io/mm-iot-sdk/framework/doc/html/index.html) ---
**Author:** ![amaljishnuinthings7](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@amaljishnuinthings7](https://community.morsemicro.com/u/amaljishnuinthings7)\ **Post date:** [October 21, 2026, 12:01pm UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/19 "2026-10-21T12:01:38Z")
I downloaded version 1.8.4 for the MM6108 board, added the Morse Micro IoT 1.0.0 Pack, and flashed the firmware to the board. However, the board is not working, and no logs are being received. What could be the reason? @ajudge @ldennis ![Screenshot 2026-10-21 172916](https://us1.discourse-cdn.com/flex001/uploads/morsemicro/original/2X/b/b14e714b479a7625719b4696c805eb8863964cd3.png) ---
**Author:** ![ajudge](https://avatars.discourse-cdn.com/v4/letter/a/c2a13f/32.png) [@ajudge](https://community.morsemicro.com/u/ajudge)\ **Post date:** [October 22, 2026, 11:01pm UTC](https://community.morsemicro.com/t/schematic-review-for-mm8108-mf15457-halow/1990/20 "2026-10-22T23:01:04Z")
Can I suggest downloading 1.11 instead, and going through the user guide available at [https://www.morsemicro.com/resources/user\_guides/MM-IoT-CMSIS-Pack-User-Guide.pdf](https://www.morsemicro.com/resources/user_guides/MM-IoT-CMSIS-Pack-User-Guide.pdf)