HL7800 no power to SIM

Having problems with an HL7800.
The module is not able to talk to the SIM.
No power seems to be getting to it from UIM1_VCC.
UIM1_DETECT is tied high via a 100k resistor. No difference if tied directly to 1.8V

I also get strange results when asking about the SIM

According to the AT reference, I should get either…

​or +CME ERROR: ​

But all I get is a single word ERROR

I also tried to manually feed the SIM card with 1.8V…….but nothing.

Any help would be appreciated.

Suggest check first with HL78 development kit.

Yes I agree. Which is what I did.
Things work normally in the kit As expected.

I went so far as to mimic the circuitry around the SIM that the kit has on our prototype. But no joy.

Then I suggest you contact with Sierra sales/technical support person,
and ask for a schematic review.
Or share your part of SIM circuit schematic here to see if somebody can help.

Okay. My support person is away, so I’ll attach my schematic.

Here’s a link to the HL7800 sheet

HL7800 Schematic

One thing not on this schematic is that I have tied the SIM detect high for testing. Though the documentation says it can be left floating.

Yes, I am having the same trouble, and before I read your post. No joy…

I cant see either the 1.8V rail for the sim coming up, or any activity on the serial clock lines.


If you tied UIM1_DET (pin 64) to 1.8V, then the SIM interface HW design is OK.

Not sure what is wrong with the design. Please contact technical support person for design review and sample evaluation.

I am having the same issue. But I have the UIM1_DET(pin 64) floating as it says in the datasheet.

I had it both floating and tied high as well, but it made no difference.

I had an SE take a look at it and he said he got my prototype to work but he had to change the SIM card holder. I’m expecting it back from him soon and will be able to share what his findings are.

You also need to be running the lates HL78 firmware which is in Beta.

-Henrique Reis

OmegaWorks Inc

Ok. I had the HL78 firmware that comes with the device. I would try to update to the latest beta and try again.
Could you please post where I can find the latest firmware for the hl78? I haven’t been able to…

Thanks !

BHL7800. (3 MB) BHL7800. (1.2 MB)

Please remove .z in the filename and unzip it.

I have updated the module to version you provided but I still have the same issue.
2019/05/31 22:53:05
Legato RTOS: 18.09.2.ALT1250.rc14 2019/05/28 19:45:55
atSwi: 16.00
UBOOT: 01.03
Apps: RKAPP_02_01_01_00_48__924f867b77e881511a058851877a5fdd71d8a107
PHY: 12.50.212633
PMP: 212636

ibs92, what SIM card holder are you using? what part number is it?

The only thing that my SE did was change out the sim card holder and the sim card lights up.

Hi Rique,

It seems my issue its also with the card holder. I have soldered some cables from the HL7800 directly to the SIM without any card holder ( to discard the card holder issue) and it works.

I am going to check my design, maybe there is some issue with the card holder library. Not sure yet. The card holder I am using is this one: http://katalog.we-online.de/em/datasheet/693043020611.pdf


Are you setting the sim up in anyway?
I get two voltage spikes from 0 to 1.8V that lasts for about 50ms.

when I try to do the AT+CCID?, I still get ERROR