VF3x reset, serial bootload

[MehmetAliIpin]

I am trying to have our VF3x to reset and accept the 0x23454523 command from the serial channel and transmit back to the terminal.

I measured:

• 3.25 Volt on VBAT pin
• 3.3 Volt on VDD_LDOIN ( about 100 milihundred volt noise)
• 1.13 Volt on DCAP_V11_LDO_OUT
• 2.52 Volt on DCAP_V25_LDO_OUT
• 3.3 Volt on VDD33
• 3.3 Volt on VDDREG
• 1.2 Volt on VDD
• 5.2 Volt on USB_VBUS
• 3.1 Volt on USB_DCAP
• 1.8 Volt on VBCTRL

23.99 MHz on XTAL-EXTAL pins ( XTAL pin has perfect sine wave, while EXTAL pin has a periodic signal between sine wave and triangle wave)

There are a 2.2 MOhm parallel resistor in ref design for XTAL pins' series capacitor. Why it is used?

The PCB draws 86 mAmperes from 3.3 Volt supply.

My RCON Mappings are adjusted for serial boot loader from UART 0. But I could not get answer to 0x23454523 message.

Do these voltage values and osc. value proof that chip has reset?

What else I could check?

[naoumgitnik]

Dear Mehmet,

1.    Are you using our Tower Reference Board or your own design?

2.    At the first glance the voltages are looking alright.

3.    Regarding the XTAL-EXTAL pins - may I see the oscilloscope screenshots, please?

4. Regarding the 2.2 MOhm resistor - mentioned i the Errata (http://cache.freescale.com/files/32bit/doc/errata/VYBRID_1N02G.pdf?fsrch=1&WT_TYPE=Errata&WT_VENDOR=...):

• e7128: XTAL: In some cases the 24MHz oscillator start-up is slow.
• Workaround: A 2.2 MΩ resistor from XTAL to ground will make the startup times reasonable.

5. Regarding the 86mA current – hard to judge without knowing your configuration settings details, but definitely nothing catastrophic.

6. Except for UART, what other possible “boot sources” do you have - SD, FLASH, etc.? If Vybrid is not configured properly, it boots from another “source” – have you seen activity on any of the related buses, especially the UART one (I guess, in your case it is USB)?

Sincerely, Naoum Gitnik.

[MehmetAliIpin]

Dear Naoum,

Thank you for your helps:

1. We are using our Own design

2. I checked the power sequence, and saw that the USB_V0 has the only 10 micro second after the 5 Volt is applied, while the 1.1V Vdd has 100 microsecond delay. There was a load switch between external 5 Volts to USB_V0, which was controlled by BCTRL signal. But it was not working, so I removed it, but I could not see any improvement.

3. blue line is for XTAL. I noticed that the voltage level (600 mVolt) is below then the requirement (Vdd*0.75= 825 mVolt), and re-measured the voltages with another calibrated oscilloscope as 850 mVolts and 888 mVolts. So the voltage levels are in the acceptable range. I am not using the exact crystal in the reference design, instead, I am using NX3225SA-24.000000MHZ which was for i.mx258 ref. design

4. If it does not stop the processor reset/boot, I don't care the slow start-up at the moment, but I also added 1 MOhms, but could not bootloader to start.

6. I have an UART/RS232 chip (ADM3101E) for UART_0, and set the BOOT_MODE_1=0 and BOOT_MODE_0=1 for serial bootload, and RCON21=RCON20=0 for UART_0. I am using PTB10,PTB11 pins for UART_0. I saw 0x23454523 pattern is coming to the RX pin, but nothing is in TX pin. I am not using RTS and CTS pins of UART_0, I wonder if bootloader needs them? I am using same 74LC541 chips for bootloader config pins, and checked that the config pins status are applied to the processor during 1 miliseconds reset.

Best regards.

Mehmet Ali

[naoumgitnik · Accepted solution]

Dear Mehmet,

Based on the data provided, I do not think your issue is related to the crystal oscillator.

Nowadays, with highly configurable devices, the vast majority of debug issues are due to incorrect configuration settings. Quite often the registers do not accept values they are supposed to get, so I would recommend you to always verify their values (read back) every time you write them.

If the device’s boot source is configured but you still do not see anything on the TX line, please, verify if your UART flow control is configured properly (see ‘49.4.1.6 Hardware flow control’, ‘49.4.1.7 Transceiver driver enable’, and ‘49.4.2.7 Hardware flow control’).

If the flow control signals, RTS and CTS, are involved, you will have to “cheat” Vybrid by pulling them up or down (see the UART physical layer details), either with external resistors or better with the built-in ones.

Just to confirm, the RTS and CTS (flow control) line do not come to the DB9 connector on one of our boards.

You may also take a look at our MQX drivers to see how the UART is handled – our SW is usually commented quite well.

(BTW, the ADM3101E is just a level-shifter in this case.)

Sincerely, Naoum Gitnik.

[MehmetAliIpin]

Dear Naoum

When I connected the RTS pin to CTS pin, the Vybrid answered the 0x23454523 pattern.

Now we need serial downloader SW like ATK for i.mx. in order to download and run our SW from internal RAM.

Do you know is it ready, or when it will be ready?

Thanks for all your helps and best regards.

[danielbasilio]

Hello Mehmet

You mentioned above that when you 'connected the RTS pin to CTS pin, the Vybrid answered the 0x23454523 pattern'. May I ask what UART parameters you used ? I am attempting the same thing with 1 start bit and 1 stop bit for each byte in the pattern at a baud rate of 115200bps, but I dont seem to be getting a response from the Vybrid.

Thanks in advance

Best Regards

Daniel

[MehmetAliIpin]

Dear Daniel,

I used the same UART parameters: 1 start,1 stop bits, no parity, 115200. Send 0x23, 0x45,0x45,0x23 (Hex bytes).

Make sure (with Oscilloscope ) you send these 4 bytes,

If you send them, but not receive back them

Check if processor generates the LDO output voltages,

Check if your reset pulse is correct

Check the processor generates the clock pulses at the clock pins

Check if your power sequence is correct (first 3.3V, then 1.2 V).

BR

[danielbasilio]

Hello Mehmet

Many thanks for your help and quick response. I am getting a response from the Vybrid now. I was waiting too long after startup before sending down the 0x23454523 pattern.

Kind Regards

Daniel

[richarddonkin]

Hello Mehmet,

I believe Freescale is working on an SDP serial downloader, but it is not released yet (see Vybrid USB Loading Utility).

In the meantime, you might find the Toradex utility useful, at toradex/imx_loader · GitHub. It is licenced under the GPLv3.

Best regards,

Richard Donkin

[MehmetAliIpin]

Dear Richard ,

Thank you for your helps.

Now we can download our image files with last version of MFGToolkit over USB.

Regards.