Archives
-
Clock source fuses startup time
Hey guys; I know I should know this from working with AVRs for so long, but I have never known?! I guess I just never had a reason to investigate it before; but the datasheet does not explain why.
When you select a clock source you also must select the startup time and such; for example on those fuse calculators; you can select like:
Quote:
High Freq – Startup-Time 6CK + 4ms
High Freq – Startup Time 256CK + 2ms
and so on…I always assumed thats just for allowing the power to even out and/or giving yourself a bit of time to enable other peripherals before the MCU starts or whatever; but I don’t know forsure…
What is the purpose of selecting start-up times? And what are some examples of when to select XCK amp Xms over say XCK amp Xms?
Thanks.
Related Forum Messages
- AVR fuses woes …
- Clock fuse settings in AVR
- Setting ports high on startup
- ATtiny2313 Fuse bits configuration
- EM-406a startup time
- Startup time
- Startup Clock HSI
- External crystal oscillator fuses
- Attiny2313 fuse problem
- MPLAB 8.63 startup problem
- RTC Software
- Delay of picaxe startup.
- On startup, start loop at beginning of next minute
- Startup settings
- Startup Problem
- Atmega48 fuse settings for external ceramic resonator
- [BitCloud] Network Startup Difficulty
- Startup Delay
- MCU Clock issues
- Fuses won’t program/osc not running
Anybody here a Mac-o-phile and using AVRFuses (http://www.vonnieda.org/software/avrfuses)? I've killed one ATMega8515 and I since I have only one spare, I'd like to get this right. All I'm trying to do is to use an 8MHz external crystal. In the current version of AVRFuses, there's no listing for an 8MHz crystal. There's listings for "Ext. RC Osc. 3.0 MHz - 8.0 MHz," with various startup times, and "Ext. RC Osc. 8.0 MHz - 12.0 MHz," with similar various startup times. But those are *oscillators*, right? Not crystals. But even if that's right, should I pick the 3-8 or the 8-12? Default startup ...Hi all, I am using ATMEGA169p uC for my development and for this, i am seeing so many clock selection settings in fuses page. When i have gone through the section in datasheet, it looks like most of the settings will work in the same way. Then why do we have these many differnt options available? Let us take for example can anybody explain me difference between the following two fuse values Ext Crystal Osc 8Mhz - Startup time 16K CK + 65mSec and Ext Crystal Osc 3Mhz - 8Mhz Startup time 16K CK + 65mSec In my development i ...HI, In the watch window of mplab all the port pins start up with a low, is there a way that i can select in the stimulus register or somewhere that one of them starts up with a high everytime the prosessor gets reset. I know that i can go to the asynch tab and select a pin to toggle during run, but i don't want to do that, i just would like RA7 to start up with a high from the beginnning. Anybody know what i can do here? Thanks RoyHello to everybody , this is the first time I am using ATtint2313 and I have to set the controler`s FUSE bits . I have used since now ATmega32/16 and a friend of mine helped me with the bits configuration , now I am by my self . I will use 8 MHz crystal , and do not want to use internal divider by 8 , want to use the reset pin as a reset of the controller . This is what I have done for now (using SPI Flash programmer 3.7) and I need a second opinion: (1-gtmarked , ...Hello, I am new here. I have been struggling getting data from an EM-406a and was wondering if it is me, or do I have a bad EM-406a. The Setup: USB FTDI TTL-232 cable connecting my PC with the GPS shield which is fitted with an EM-406a. Using a terminal emulator, I am able to connect to the EM-406a and recieve data from it. The troulbe is, it takes about 30 minutes to see any satalites are report co-ordinates. Once it sees some satalites, all is better. I was hoping for a faster startup time than this. The datasheets says 42 second Cold Start. I suspect the long startup ...Hello, I am using AT91SAM7x256 with keil ARM compiler .After giving an external reset the control comes to the "main" after 1.5seconds(approx). How can i reduce this startup time...Thanks in advance! regardsI'm simply looking to have the STM32F4 startup using the HSI clock (at the default 16MHz). How best can this be accomplished (if it's not already default). What clock does the STM32F4 natively startup using? I was thinking this would work: static void SetSysClock(void) { /* RCC system reset(for debug purpose) */ RCC_DeInit(); // Enable HSI Clock and wait until it's ready RCC_HSICmd(ENABLE); while(RCC_GetFlagStatus(RCC_FLAG_HSIRDY) == RESET); }Hey I have a crystal (11,0592MHz) with two 22nF capacitors attached to an ATMega32, the correct way. Now when I program the fusebits on external crystal, high frequency with startup-time of 64ms, it doesnt work... Is the startup-time so important? If yes, how do I calculate it? I am using AVRStudio4 build 684 with an AVRISPMK2 programmer Greetings KoenI wanted to run my attiny2313 at 8MHz using an external crystal for USART connectivity. I read through the information on fuses in the datasheet and calculated the high fuse to be the default 0xDF and the low fuse to 0xFD. I double checked using online fuse calculator http://www.engbedded.com/fusecalc/ According to the settings, 1. the clock should not be divided by 8 2. freq range= 3.0-8.0 3. startup time= 14CK + 65ms I connected a 8MHz crystal across pins 4amp5 and connected 18pF capacitors to pin 4amp5 and grounded the other end of capacitors. Now when i try to do ...Did you noticed that 8.63 requires very long time to start? During startup IDE several times runs all Hi-Tech compilers and queries some info. Example: picc.exe --q --help=xxxxx. I did not noticed this in previous version. Isn't there some better way to do it?So, after the London Raspberry Pi Faces Meetup, I've ordered a cover for my raspberry pi, as well as a breadboard, RTC chip (1307), and all the other random stuff you need (cables, crystal, smoothing capacitor, battery, etc). I plan to connect the RTC to the Raspberry Pi over I2C. I understand it won't work automatically, but I'll need to write a short program which will run at startup, and which I hope will look something like this: Code: Select all Can I get the time from an NTP server? If Yes { Set RPi clock to time from NTP server ...Hello everyone. I did some tests last night I wanted to know the approximate time between switching on a PICAXE (a 08M) and for example the lighting of a LED with a simple program like: main: high 1 goto main I fed a 08M through the release of another 08M with which I set as a program: main: pause 100 high 1 pause 100 low 1 goto main I realized by changing the values of "pause" it takes about 75 milliseconds for the LED to illuminate. Turning on of the 08M (startup) lt---- 75 ms -----gt LED Lighting That seems very long, a friend told me that with its pic at him (ASM ...I am reading multiple sensors with the arduino and logging that data to an SD card. I do not have a real time clock, so to set the time on startup I send a message over the serial port from the unix terminal. However, I do not want the main loop to start reading the sensors until the start of the next minute once the time value is received by the arduino (i.e., if the time sent over serial port is 11:41:25, delay the start of the loop until 11:42:00). I've looked around the forum for a while to find ...When mplab starts on my system it defaults to no programmer selected, no simulator and debug. As I always use pickit2 and mplab sim I would like to set them to be active as mplab loads. Also release is usually where I start just to eliminate halt on first errors coming up. Also the default clock in debugger settings is 20mhz, it would be better for me at the moment if it defaulted to 4mhz. Is there a way to make these choices permanent so I don't have to select them each time I start Mplab IDE?Hi, I need some ideas on a problem I'm experiencing. I have an STM32F2xx based product (an automotive sensor of sorts) which has just started field testing. The electrical interface to the product is 4 wires - +V, GND, CAN+ and CAN-. Most of the time the product starts fine (as observed by the CAN stream), but every so often the product does not appear to start. I have not yet personally observed the fault - only seen the evidence of it. There are two variations: 1) If the product starts correctly, then it does not appear to stop working at any stage. 2) ...I have not used Atmega devices for such a long time. This time I am helping a friend with Atmega48 with an external 16 MHz ceramic resonator (digikey part 490-1214-ND, built in capacitors of 30 pf). Using AVR Studio 5 and AVRISP-MkII, the most logical choice to enable the external resonator seems to be setting the fuses as. Quote: CKDIV : unchecked CKOUT : unchecked SUT_CKSEL : XTFXTAL_16KCK_14CK_65MS Which I assume means External fast crystal with maximum startup time. However, with this setting, as well as any other settings I have tried, the device dies and the fuses cannot be programmed ...We are encountering a startup issue with a test network and I was wondering if this is expected behavior or something wrong with our cfg settings. We have a network of all routers (1 coord). They are currently pretty much co-located, all placed in a slot in a tray on a lab bench. We have the WSNDemo application loaded on the devices with unmodified CS settings CS_CHANNEL_MASK 1 CS_CHANNEL_PAGE 0 CS_MAX_CHILDREN_AMOUNT 8 CS_APS_DATA_REQ_BUFFERS_AMOUNT 3 CS_MAX_CHILDREN_ROUTER_AMOUNT 2 CS_APS_ACK_FRAME_BUFFERS_AMOUNT 2 CS_NWK_BUFFERS_AMOUNT 4 CS_NEIB_TABLE_SIZE 8 CS_ROUTE_TABLE_SIZE 10 CS_ADDRESS_MAP_TABLE_SIZE 2 CS_ROUTE_DISCOVERY_TABLE_SIZE 3 CS_DUPLICATE_REJECTION_TABLE_SIZE 8 CS_NWK_BTT_SIZE 8 If we power on 16 devices at the ...Anyone have a good idea on how to get rid of the startup delay? I want to use the GPIOs to bit bang a SPI bus, and I have it sort of working, but there is a 10-15 second delay on startup that locks up my circuit board. I tried going into the start of the BSP and setting all of the IOs to inputs (tri-state), but that only gained me a second or two. Why on earth does it sit there doing nothing for so long? -ErikHello there, According to the PIC16f887 datasheet: Quote: "When the internal clock source is selected the TMR1H:TMR1L register pair will increment on multiples of FOSC as determined by the Timer1 prescaler." I'm trying to do some reading of the TMR1H and TMR1L and all i get are multiples of 8. If my guess is right, I'm getting multiples of 8 because i selected internal osc, with 8 MHz. In the mikroC program, i've set the Timer1 register as follows: Code: Select all T1CON = 0b00000100; So, according to 16f887 datasheet... Quote: bit 7 T1GINV: Timer1 Gate Invert bit(1) 1 = Timer1 gate is active-high (Timer1 counts when gate is high) 0 = Timer1 ...After using ATMega processors for 6 years, I am having a lot of trouble lately getting Mega644P processors to program. Only certain boards, only certain processors on those boards. Some boards work fine. The crystal oscillator does not seem to be running, and the fuses just won't program. Crystals all test OK. On one board, the fuses did program OK, but when I changed the last fuse from "Ext cystal osc 8.0MHz- startup time..." to "Internal R/C", now it won't program at all and won't let me re-select the original fuse. Brian