Electronic Components Datasheet Search |
|
ICM7249IPM Datasheet(PDF) 7 Page - Intersil Corporation |
|
ICM7249IPM Datasheet(HTML) 7 Page - Intersil Corporation |
7 / 9 page 29 Detailed Description As the Functional Diagram shows the device consists of the following building blocks: • A 32.768kHz crystal oscillator with the associated dividers to generate timebase signals for periods of 1s (frequency of 1Hz), 6s (1/10 min) and 36s (1/100 hour), and 32Hz signal for LCD drivers. • A debounce/high-pass detect circuit for the S/S (Start/Stop) input. • A chain of cascaded decade counters, 3 decade counters for prescaling and 51/2 BCD decade counters for display driving. • Display control circuitry and BCD to 7-segment decoder/ drivers. • A control decoder to select different modes of operation. This is done by routing different signals to the different points in the chain of decade counters. The control decoder has 4 inputs for selecting 16 possible modes of operation, numbered 0 to 15. The 16 modes are selected by placing the binary equivalent of the mode num- ber on inputs C0 to C3. Table 2 shows the control inputs and the modes of operation. After applying power, the ICM7249 requires a rise time of tr to become active and for oscillation to begin, as shown in Figure 1. The BP (backplane) output changes state once every 512 cycles of the crystal oscillator, resulting in a square wave of 32Hz. The display segments drive signal has the same level and frequency as BP. Segments are off when in phase with BP and are on when out of phase with BP. A non-multiplexed LCD display is used because it is more stable over temperature and allows many standard LCD displays to be used. Timer Mode of Operation In modes 0 to 3 the device functions as an interval timer. In this mode, one of the timebase signals will be routed to the decade counters at a proper point in the chain. Depending on the selected mode the display will be incremented at 0.1 min, 0.01 hour, 0.1 hour or 1 hour rates. Control of timing function is handled by the S/S input. There is a high-pass filtering effect on the S/S input in timer modes. Referring to Figure 2, timing is active when either S/S is held high for more than 12.5ms, or if input frequency is 50Hz to 120kHz. Driving S/S with a frequency between 40Hz to 50Hz has an indeterminate effect on timing and should be avoided. Note that the tHP intervals shown on Figure 1 are also applied to the intervals when the S/S input is low. Counter Mode of Operation In modes 4 to 11 the device functions as an event counter or totalizer. In this mode the S/S input will be routed to the decade counters at a proper point in the chain. Each positive transition of the S/S will be registered as one count. Depending on the selected mode, the display will be incremented by each pulse, every 10 pulses, every 100 pulses or every 1000 pulses. In counter modes 4, 6, 8 and 10 the S/S input is subjected to 31 91 Seven-Segment LCD Output. 32 e1 Seven-Segment LCD Output. 33 d1 Seven-Segment LCD Output. 34 c1 Seven-Segment LCD Output. 35 b1 Seven-Segment LCD Output. 36 a1 Seven-Segment LCD Output. 37 W Wink-Segment Output. 38 BP Backplane for LCD Reference. 39 VDD Positive Supply Voltage. 40 OSC IN Quartz Crystal Connection. 41 OSC OUT Quartz Crystal Connection. 42 GND Supply GRouND. 43 C0 Mode-select Control Input. 44 C1 Mode-select Control Input. 45 C2 Mode-select Control Input. 46 C3 Mode-select Control Input. 47 S/S Start/Stop Input. 48 DT Display Test Input. TABLE 1. MODE SELECT TABLE MODE CONTROL PIN INPUTS FUNCTION C3 C2 C1 C0 0 0000 1 Hour Interval Timer 1 0001 0.1 Hour Interval Timer 2 0010 0.01 Hour Interval Timer 3 0011 0.1 Minute Interval Timer 4 0100 1’s Counter with Debounce 5 0101 1’s Counter 6 0110 10’s Counter with Debounce 7 0111 10’s Counter 8 1000 100’s Counter with Debounce 9 1001 100’s Counter 10 1010 1000’s Counter with Debounce 11 1011 1000’s counter 12 1100 Test Display Digits 13 1101 Internal Test 14 1110 Internal Test 15 1111 Reset PIN NAME DESCRIPTION ICM7249 |
Similar Part No. - ICM7249IPM |
|
Similar Description - ICM7249IPM |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List 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 |