 |
Os motores de busca de Datasheet de Componentes eletrônicos |
|
|
Os motores de busca de Datasheet de Componentes eletrônicos |
|
AD7889 Folha de dados(PDF) 31 Page - Analog Devices |
|
||||||||||||||||||||||||||||||
AD7889 Folha de dados(HTML) 31 Page - Analog Devices |
|
|
31 / 40 page  Data Sheet AD7879/AD7889 Rev. D | Page 31 of 40 INTERRUPTS The AD7879/AD7889 have a dual function interrupt output, INT, as well as a pen-down interrupt, PENIRQ. The INT output can be configured as a data available interrupt (DAV), as an out of limit interrupt (INT), or as a GPIO interrupt. DAV—Data Available Interrupt The behavior of the interrupt output is controlled by Bit 13 in Control Register 3. In default mode (Bit 13 = 0), INT operates as a data available interrupt (DAV). When the AD7879/AD7889 finish a conversion or a conversion sequence, the interrupt is asserted to let the host know that new ADC data is available in the result registers. While the ADC is idle or is converting, DAV is high. When the ADC finishes converting and new data has been written to the result registers, DAV goes low. Reading the result registers resets DAV to a high condition. DAV is also reset if a new conversion is started by the AD7879/AD7889 because the timer expired. The host reads the result registers only when DAV is low. To ensure correct operation of the DAV mode when using the SPI interface, it is necessary to write 0x0000 to Register 0x81 after a set of register reads. This write clears the internal data read signal. ADC CONVERTING SETUP BY HOST IDLE NEW DATA AVAILABLE HOST READS RESULTS IDLE tCONV AD7879 STATUS DAV Figure 35. Operation of DAV Output When the on-board timer is programmed to perform automatic conversions, limited time is available to the host to read the result registers before another sequence of conversions begins. The DAV signal is reset high when the timer expires, and the host should not access the result registers while DAV is high. INT—Out of Limit Interrupt The INT pin operates as an alarm or interrupt output when Bit 13 in Control Register 3 (Address 0x03) is set to 1. The output goes low if any one of the interrupt sources is asserted. The results of high and low limit comparisons on the AUX, VBAT, and TEMP channels are interrupt sources. An out of limit comparison sets a status bit in the interrupt register. A separate status bit for the high limit and the low limit on each channel indicates which limit was exceeded. The interrupt sources can be masked by setting the corresponding enable bit in this register to 1. There is one enable bit per channel. PENIRQ—Pen Interrupt The pen interrupt request output (PENIRQ) goes low whenever the screen is touched and the PENIRQ enable bit is set to 0 (Control Register 1, Bit 15). When PENIRQ enable is set to 1, the pen interrupt request output is disabled. The pen interrupt equivalent output circuitry is shown in Figure 36. This digital logic output has an internal 50 kΩ pull-up resistor, so it does not need an external pull-up. The PENIRQ output idles high, and the PENIRQ circuitry is always enabled in master mode (ADC mode = 11), except during conversions. X+ TOUCH SCREEN Y+ 50kΩ Y– X– PENIRQ ENABLE PENIRQ VCC VCC Figure 36. PENIRQ Output Equivalent Circuit When the screen is touched, PENIRQ goes low. This generates an interrupt request to the host. When the screen touch ends, PENIRQ immediately goes high if the ADC is idle. If the ADC is converting, PENIRQ goes high when the ADC becomes idle. The PENIRQ operation for these two conditions is shown in Figure 37. SCREEN PENIRQ ADC STATUS TOUCHED NOT TOUCHED NOT TOUCHED NOT TOUCHED NOT TOUCHED ADC IDLE SCREEN PENIRQ ADC STATUS TOUCHED ADC IDLE ADC CONVERTING ADC IDLE RELEASE NOT DETECTED PENIRQ DETECTS RELEASE PENIRQ DETECTS RELEASE PENIRQ DETECTS TOUCH PENIRQ DETECTS TOUCH Figure 37. PENIRQ Operation for ADC Idle and ADC Converting |
Nº de peça semelhante - AD7889 |
|
Descrição semelhante - AD7889 |
|
|
Ligação URL |
| Privacy Policy |
| ALLDATASHEETPT.COM |
| ALLDATASHEET é útil para você? [ DONATE ] |
Sobre Alldatasheet | Publicidade | Contato conosco | Privacy Policy | roca de Link | Lista de Fabricantes All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
Portuguese ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
