Electronic Components Datasheet Search |
|
ST16C580IQ48 Datasheet(PDF) 11 Page - Exar Corporation |
|
ST16C580IQ48 Datasheet(HTML) 11 Page - Exar Corporation |
11 / 39 page ST16C580 11 Rev. 1.22 C1 22pF C2 33pF X1 1.8432 MHz R1 50-120 R2 1M Crystal oscillator connection level. In this case the 580 FIFO may hold more charac- ters than the programmed trigger level. Following the removal of a data byte, the user should recheck LSR bit- 0 for additional characters. A Receive Time Out will not occur if the receive FIFO is empty. The time out counter is reset at the center of each stop bit received or each time the receive holding register (RHR) is read (see Figure 10, Receive Time-out Interrupt). The actual time out value is T (Time out length in bits) = 4 X P (Programmed word length) + 12. To convert the time out value to a character value, the user has to consider the complete word length, including data information length, start bit, parity bit, and the size of stop bit, i.e., 1X, 1.5X, or 2X bit times. Example -A: If the user programs a word length of 7, with no parity and one stop bit, the time out will be: T = 4 X 7( programmed word length) +12 = 40 bit times. The character time will be equal to 40 / 9 = 4.4 characters, or as shown in the fully worked out ex- ample: T = [(programmed word length = 7) + (stop bit = 1) + (start bit = 1) = 9]. 40 (bit times divided by 9) = 4.4 characters. Example -B: If the user programs the word length = 7, with parity and one stop bit, the time out will be: T = 4 X 7(programmed word length) + 12 = 40 bit times. Character time = 40 / 10 [ (programmed word length = 7) + (parity = 1) + (stop bit = 1) + (start bit = 1) = 4 characters. Programmable Baud Rate Generator The 580 supports high speed modem technologies that have increased input data rates by employing data compression schemes. For example a 33.6Kbps modem that employs data compression may require a 115.2Kbps input data rate. A 128.0Kbps ISDN modem that supports data compression may need an input data rate of 460.8Kbps. The 580 can support a stan- dard data rate of 921.6Kbps. Single baud rate generator is provided for the trans- mitter and receiver, allowing independent TX/RX channel control. The programmable Baud Rate Gen- erator is capable of accepting an input clock up to 24 MHz, as required for supporting a 1.5Mbps data rate. The 580 can be configured for internal or external clock operation. For internal clock oscillator operation, an industry standard microprocessor crystal (parallel reso- nant/ 22-33 pF load) is connected externally between the XTAL1 and XTAL2 pins, with an external 1 M resistor across it. Alternatively, an external clock can be connected to the XTAL1 pin to clock the internal baud rate generator for standard or custom rates. The generator divides the input 16X clock by any divisor from 1 to 216 -1. The 580 divides the basic crystal or external clock by 16. Further division of this 16X clock provides two table rates to support low and high data rate applications using the same system design. The two rate tables are selectable through the internal register, MCR bit-7. Setting MCR bit-7 to a logic 1 provides an additional divide by 4 whereas, setting MCR bit-7 to a logic 0 only divides by 1. (See Table 4 and Figure 11). The frequency of the - BAUDOUT output pin is exactly 16X (16 times) of the selected baud rate (-BAUDOUT =16 x Baud Rate). Customized Baud Rates can be achieved by selecting the proper divisor values for the MSB and LSB sec- tions of baud rate generator. Programming the Baud Rate Generator Registers |
Similar Part No. - ST16C580IQ48 |
|
Similar Description - ST16C580IQ48 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | 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 |