AT91SAM7 TWI DRIVER DETAILS:
|File Size:||30.6 MB|
|Supported systems:||Windows Vista, Windows Vista 64-bit, Windows XP 64-bit, Mac OS X, Mac OS X 10.4, Mac OS X 10.5|
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AT91SAM7 TWI DRIVER
At91sam7 twi of the eight analog pins are buffered and available on PCB pads. Ignored, if the maximum number of bytes to receive is zero. Set at91sam7 twi zero, if no bytes are expected from the slave device. Returns: The number of bytes received, -1 in case of an error or timeout.
Receive data at91sam7 twi a master from a device having internal addressable registers. Writing any other value in this field aborts the write operation. The reset controller is ready for a software command. The reset controller is busy. It is built around a bit counter fed by Slow Clock divided by a programmable bit at91sam7 twi.
The bit counter can count up to seconds, corre- sponding to more than years, then roll over to 0. The Real-time Timer can also be used as a free-running timer with a lower time-base. Programming RTPRES to 1 or 2 is possible, but may result in losing status events because the status register is cleared two Slow Clock cycles after read. To prevent several executions of the interrupt handler, the interrupt must be disabled in the interrupt handler and re-enabled when the status register is clear. As this value can be updated asynchronously from the Master Clock, it is advis- able to read this register twice at the same value to improve accuracy of the returned value.
This bit can be used to start a periodic interrupt, the period being one second when the RTPRES is pro- grammed with 0x and Slow Clock equal to This also resets the bit counter. RTT This assures effective optimization of the pins at91sam7 twi a product. The PIO Controller also features a synchronous at91sam7 twi providing up to 32 bits of data output in a single write operation.
at91sam7 twi As the multiplexing is hard- ware-defined and thus product-dependent, the hardware designer and programmer must carefully determine the configuration of the PIO controllers required by their application. Writing any of the registers of the user interface does not require the PIO Controller clock at91sam7 twi be enabled. However, when the clock is disabled, not all of the features of the PIO Controller are available. Note that the Input Change Interrupt and the read of the pin level require the clock to be validated. After a hardware reset, the PIO clock is disabled by default. The user must configure the Power Management Controller before any access to the input line information.
This means that the PIO Controller interrupt lines are connected among the interrupt sources 2 to In this description each signal shown represents but one of up to 32 possible indexes.
Peripheral A Input. After reset, all of the pull-ups are enabled, i. A value of 1 indicates the pin is controlled by the PIO controller. However, in some events, it is important that PIO lines are controlled by the periph- eral as in the case of memory chip select at91sam7 twi that must be driven inactive after reset or for address lines that must be driven low for booting out at91sam7 twi an external memory.
Antmicro · I2C in eCos on AT91SAM7 platforms
For each pin, the corresponding bit at level 0 means peripheral A is selected whereas the corre- sponding at91sam7 twi at level 1 indicates that peripheral B is selected. Note that multiplexing of peripheral lines A and B only affects the output at91sam7 twi. The peripheral input lines are always connected to the pin input. This may lead to unexpected transient values.
An external pull-up resistor or enabling of the internal one is generally required to guar- antee a high level on the line. After reset, the Multi Drive feature is disabled on all pins, i. The filter introduces one Master Clock cycle latency if the pin level change occurs before a rising edge. However, this latency at91sam7 twi not appear if the pin level change occurs before a falling edge.
This is illustrated in Figure When the glitch filter is enabled, it does not modify the behavior of the inputs on the peripherals. The glitch filters require that the PIO Controller clock is enabled. Input At91sam7 twi Filter Timing. MCK up to 1. The interrupt signals of the thirty-two channels are ORed-wired together to gen- erate a single interrupt signal to the Advanced Interrupt At91sam7 twi. Each register is 32 bits wide.
Undefined bits read zero. However, at91sam7 twi first read of the register may read a different value as input changes may have occurred.
AT91SAM7-64 and TWI (i2C) with FM24C64
Only this set of registers clears the status by writing 1 in the first register and sets at91sam7 twi status by writing 1 in the second register. The pin is driven at high and low level.Hello. I have some probloems with my AT91 and a fram i connected via the TWI.
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I am using the sample code from the atmel-homepage. I'm confused which pins to use for TWI (I2C) on the AT91SAM7S.