 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
DS87C520 Datasheet(PDF) 6 Page - Maxim Integrated Products |
|
||||||||||||||||||||||||||||||
DS87C520 Datasheet(HTML) 6 Page - Maxim Integrated Products |
|
|
6 / 43 page  DS87C520/DS83C520 EPROM/ROM High-Speed Microcontrollers 6 of 43 PIN DESCRIPTION (continued) PIN DIP PLCC TQFP NAME FUNCTION 21 24 18 P2.0 (A8) 22 25 19 P2.1 (A9) 23 26 20 P2.2 (A10) 24 27 21 P2.3 (A11) 25 28 22 P2.4 (A12) 26 29 23 P2.5 (A13) 27 30 24 P2.6 (A14) 28 31 25 P2.7 (A15) Port 2 (A8–15), I/O. Port 2 is a bidirectional I/O port. The reset condition of Port 2 is logic high. In this state, a weak pullup holds the port high. This condition also serves as an input mode, since any external circuit that writes to the port will overcome the weak pullup. When software writes a 0 to any port pin, the DS87C520/DS83C520 will activate a strong pulldown that remains on until either a 1 is written or a reset occurs. Writing a 1 after the port has been at 0 will cause a strong transition driver to turn on, followed by a weaker sustaining pullup. Once the momentary strong driver turns off, the port again becomes both the output high and input state. As an alternate function Port 2 can function as MSB of the external address bus. This bus can be used to read external ROM and read/write external RAM memory or peripherals. 10 11 5 P3.0 11 13 7 P3.1 12 14 8 P3.2 13 15 9 P3.3 14 16 10 P3.4 15 17 11 P3.5 16 18 12 P3.6 17 19 13 P3.7 Port 3, I/O. Port 3 functions as both an 8-bit, bidirectional I/O port and an alternate functional interface for External Interrupts, Serial Port 0, Timer 0 and 1 Inputs, and RD and WR strobes. The reset condition of Port 3 is with all bits at a logic 1. In this state, a weak pullup holds the port high. This condition also serves as an input mode, since any external circuit that writes to the port will overcome the weak pullup. When software writes a 0 to any port pin, the DS87C520/DS83C520 will activate a strong pulldown that remains on until either a 1 is written or a reset occurs. Writing a 1 after the port has been at 0 will cause a strong transition driver to turn on, followed by a weaker sustaining pullup. Once the momentary strong driver turns off, the port again becomes both the output high and input state. The alternate modes of Port 3 are outlined below. Port Alternate Mode P3.0 RXD0 Serial Port 0 Input P3.1 TXD0 Serial Port 0 Output P3.2 INT0 External Interrupt 0 P3.3 INT1 External Interrupt 1 P3.4 T0 Timer 0 External Input P3.5 T1 Timer 1 External Input P3.6 WR External Data Memory Write Strobe P3.7 RD External Data Memory Read Strobe 31 35 29 EA External Access Input, Active Low. Connect to ground to force the DS87C520/DS83C520 to use an external ROM. The internal RAM is still accessible as determined by register settings. Connect EA to VCC to use internal ROM. — 12, 34 6, 28 N.C. Not Connected. These pins should not be connected. They are reserved for use with future devices in this family. |
Similar Part No. - DS87C520 |
|
Similar Description - DS87C520 |
|
|
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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
