 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Microcontroller and PC projects : MM - Sleep Mode
| Author | Message | ||||
palcal Guru  Joined: 12/10/2011 Location: AustraliaPosts: 1873 |
I take it that there is no way of sending the MM to sleep, to be awoken with a push button. I have a project that needs to be battery operated but draws a bit too much current and battery life would be short. Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
||||
| aargee Senior Member  Joined: 21/08/2008 Location: AustraliaPosts: 255 |
No, but you can achieve something similar using a small MM controlled Mosfet or a transistor driven relay to control power to the MM. Your program would be called autorun.bas and you would kick to whole lot off with a pushbutton across the relay contacts, holding it down until the MM kicks in with autorun operating the relay, you could use a LED driven by the transistor to indicate the relay is on. When finished, the MM just removes power from the relay, zero power used until the next button push. Sorry haven't got the facilities to draw a diagram. - Rob. For crying out loud, all I wanted to do was flash this blasted LED. |
||||
Keith @ Senior Member Joined: 19/06/2011 Location: AustraliaPosts: 167 |
Paul You need to provide a bit more info on what you expect/want the MM to be doing whilst it is "asleep". See below for more info but there are ramifications depending on what choices you make! Keith 
From the PIC32 hardware manual .... This section describes power-saving features for the PIC32MX5XX/6XX/7XX family of devices. These devices offer a total of nine methods and modes, organized into two categories, that allow the user to balance power consumption with device performance. In all of the methods and modes described in this section, power-saving is controlled by software. 27.1 Power-Saving with CPU Running When the CPU is running, power consumption can be controlled by reducing the CPU clock frequency, lowering the PBCLK and by individually disabling modules. These methods are grouped into the following categories: FRC Run mode: the CPU is clocked from the FRC clock source with or without postscalers. LPRC Run mode: the CPU is clocked from the LPRC clock source. SOSC Run mode: the CPU is clocked from the SOSC clock source. In addition, the Peripheral Bus Scaling mode is available where peripherals are clocked at the programmable fraction of the CPU clock (SYSCLK). 27.2 CPU Halted Methods The device supports two power-saving modes, Sleep and Idle, both of which Halt the clock to the CPU. These modes operate with all clock sources, as listed below: POSC Idle mode: the system clock is derived from the POSC. The system clock source continues to operate. Peripherals continue to operate, but can optionally be individually disabled. FRC Idle mode: the system clock is derived from the FRC with or without postscalers. Peripherals continue to operate, but can optionally be individually disabled. SOSC Idle mode: the system clock is derived from the SOSC. Peripherals continue to operate, but can optionally be individually disabled. LPRC Idle mode: the system clock is derived from the LPRC. Peripherals continue to operate, but can optionally be individually disabled. This is the lowest power mode for the device with a clock running. Sleep mode: the CPU, the system clock source and any peripherals that operate from the system clock source are Halted. Some peripherals can operate in Sleep using specific clock sources. This is the lowest power mode for the device. 27.3 Power-Saving Operation Peripherals and the CPU can be halted or disabled to further reduce power consumption. 27.3.1 SLEEP MODE Sleep mode has the lowest power consumption of the device power-saving operating modes. The CPU and most peripherals are halted. Select peripherals can continue to operate in Sleep mode and can be used to wake the device from Sleep. See the individual peripheral module sections for descriptions of behavior in Sleep. Sleep mode includes the following characteristics: The CPU is halted The system clock source is typically shutdown. See Section 27.3.3 Peripheral Bus Scaling Method for specific information. There can be a wake-up delay based on the oscillator selection The Fail-Safe Clock Monitor (FSCM) does not operate during Sleep mode The BOR circuit, if enabled, remains operative during Sleep mode The WDT, if enabled, is not automatically cleared prior to entering Sleep mode Some peripherals can continue to operate at limited functionality in Sleep mode. These peripherals include I/O pins that detect a change in the input signal, WDT, ADC, UART and peripherals that use an external clock input or the internal LPRC oscillator (e.g., RTCC, Timer1 and Input Capture). I/O pins continue to sink or source current in the same manner as they do when the device is not in Sleep Modules can be individually disabled by software prior to entering Sleep in order to further reduce consumption The more we know, the more we know we don't know ! |
||||
| palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1873 |
All sounds very complicated. I have built auto power off circuits but they are not suitable. I am using the MM to display time, date, temperature,humidity and dewpoint temp. And working on times for high and low tide. These are displayed sequentially on a 16x2 LCD. It draws about 170ma. So if I use an auto power off device the Temperature and Humidity would come back on but I would lose the time function. I want to take this with me when I go camping and fishing. I calculate even using AA batteries it would only operate for maybe 6-8 hours. I may just have to use a gel-cell. Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
||||
TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6098 |
You could use the PCF8563 RTC. They have an alarm function which could be used to power up the Maximite. If the application is stored as autorun.bas and the first thing it does is read the RTC you are up and running again. Your application could set the RTC's alarm to when ever you need to power up again. There would be a bit of external circuitry involved but not much. It is something I have thought about but it is not high on my list of projects. Jim VK7JH MMedit Β MMBasic Help |
||||
 Print this page |
