# Error using bitvis\_vip\_gmii

**URL:** <https://forum.uvvm.org/t/error-using-bitvis-vip-gmii/128>\
**Category:** Bitvis VIP GMII\
**Tags:** question, gmii\
**Created:** [November 12, 2020, 11:34am UTC](https://forum.uvvm.org/t/error-using-bitvis-vip-gmii/128 "2020-11-12T11:34:58Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ecg173-bi](https://dub1.discourse-cdn.com/flex017/user_avatar/forum.uvvm.org/ecg173-bi/32/34_2.png) [@ecg173-bi](https://forum.uvvm.org/u/ecg173-bi)\
**Post date:** [November 12, 2020, 11:34am UTC](https://forum.uvvm.org/t/error-using-bitvis-vip-gmii/128/1 "2020-11-12T11:34:58Z")

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Hi everybody,

I am trying to create a simple project that uses bitvis\_vip\_gmii. Starting from the UART example, I have created the scripts folder and the tb and th files. Inside this last one I have

i1\_gmii\_vvc: entity bitvis\_vip\_gmii.gmii\_vvc  
generic map(  
GC\_INSTANCE\_IDX =\> 1  
)  
port map(  
gmii\_vvc\_tx\_if =\> gmii\_tx\_if,  
);

I am using gmii\_tx\_if.txd as input to other instance.

Finally, from tb, I am trying to access to the component in two ways:

1. gmii\_write((x"01", x"02"),“Write 2 bytes”, gmii\_tx\_if); → In this case, I can see all the signal in the simulator but all of them (except clks) are ‘0’.

2. gmii\_write(GMII\_VVCT, 0, TX, (x"01", x"02"), “Write 4 to DUT”); → In this case, I obtained the following error:

# KERNEL: UVVM: \*\*\* TB\_ERROR #1 \*\*\*

# KERNEL: UVVM: 100.001 ns TB seq.(uvvm)

# KERNEL: UVVM: Time out for uvvm cmd [7]: ‘gmii\_write(GMII\_VVC,0,tx, 2 bytes)’ while waiting for acknowledge from VVC

# KERNEL: UVVM:

Moreover if I extend ‘await\_completion’ the results continues being the same one.

Could someone give me some indication to help me? I am new on that and I am a bit lost.  
Thanks in advance

---

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**Author:** ![Erick](https://avatars.discourse-cdn.com/v4/letter/e/bbce88/32.png) [@Erick](https://forum.uvvm.org/u/Erick)\
**Post date:** [November 13, 2020, 7:32am UTC](https://forum.uvvm.org/t/error-using-bitvis-vip-gmii/128/2 "2020-11-13T07:32:37Z")

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Hi,

The correct way to send a command to the VVC is the option 2.  
However, you are trying to send a write command to instance 0, but your i1\_gmii\_vvc has the instance 1, therefore you’re getting that timeout.

Best regards,  
Erick

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<div class="post-metadata">

**Author:** ![ecg173-bi](https://dub1.discourse-cdn.com/flex017/user_avatar/forum.uvvm.org/ecg173-bi/32/34_2.png) [@ecg173-bi](https://forum.uvvm.org/u/ecg173-bi)\
**Post date:** [November 13, 2020, 10:48am UTC](https://forum.uvvm.org/t/error-using-bitvis-vip-gmii/128/3 "2020-11-13T10:48:26Z")

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Hi Erick,

Yes, now it works!  
Thanks 🙂