Re: FW: [68300] Say hello to everyone.
2003-09-13 by liubo
Dong Cho,\ufffd\ufffd\ufffd�\ufffd I use MC68332ACFC25 which can run 25.165824MHz,it is no difference to the MC68332ACFC16,except the clock,I don't think you need the datasheet. I know MPC555 is better than 68332,but it is too expensive,can anybody tell me where can I find a CPU like 68332 which has TPU,SPI,UART,but the system clock is much higher and has a floating point co-processor?Thanks. Liubo ======= 2003-09-12 09:47:00 \ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\u0434\ufffd\ufffd\ufffd\ufffd======= >Liubo, >Can you verify that 68332 run at 25 mhz ? >Do you have any official datasheet to support max speed is 25 mhz ? >If you do, send me datasheet please. > >All datasheet I see indicate the max speed is 20 mhz. > >Thanks, > > >-----Original Message----- >From: liubo [mailto:boliu@...] >Sent: Thursday, September 11, 2003 6:48 PM >Subject: [68300] Say hello to everyone. > > > Hi everyone! > 2 years ago,I had asked Charles Melear many questions about MC683332 >through the mailing list. >But later the mailing list dispeared.Today I finally find it in YAHOO.This >is the first time I >come here.Several days ago,I asked Charles Melear some question,I write the >question and his answers >here,maybe it is useful to you. > >> 1.CPU is also MC68332,but has many 8bit width interface IC (8 or 10 >CAN,ARCNET controllers), >>I always connect 8bit interface to D8-D15 of 68332,this time I wonder can >68332 drive so many >>IC? Do I need to add buffers(such as 74HC245)?How can I do? I think maybe I >can connect half >>of the controllers to D0-D7 of 68332,doing so maybe I can decrease the >burden of 68332? > >Liubo, > >How many devices are you planning on connecting to the data bus? > >You can connect peripherals to both the upper half and lower half of the >data bus although it presents nightmares for your software guys. Basically >you have to configure the bus as a 16 bit bus and then read the bus as a >16-bit value and mask off the portion that you do not want. The other >problem is that you have to address the buss as consecutive words as opposed >to consecutive bytes. That is, there is no address 0 line. You might be >able to use the MOVEP instruction. I have never used it but I think it is >supposed to facilitate what you are suggesting. > >> 2. I use 68332 at 25M clk,do I need to select a high speed memory chip?Is >it enough >>if I use 70ns speed chip? > >Liubo, > >I believe that the minimum access time is two full S-clock cycles. The >S-clock is essentially equal to the internal bus speed. I have not gone >through the calculations but I believe that you actually need 80 ns. memory >to run with no wait states at 25 MHZ (40 ns period). Anyway, 70 ns would >do. > >> 3.In my system,I use SPI to connect to other IO boards.In the last >design,I find that some >>time it is abnormal when I use SPI(input or output error),I think the first >reason is I choose >>the high speed SPI,but the main reason is 68332 SPI drive many SPI device >and there are distances >>about 50CM to 68332.Can I improve the quality of SPI by add buffers(74245) >at each IO boards? >>Can I do other things? > >Liubo, > >I am not sure what to tell you here. 50 cm doesn't sound like too long a >wire that it is going to give you problems. You have to use decent wire and >maybe even shielded wire. Buffers on the SPI are used all the time. > >> Thank you very much! > > liubo > boliu@... > > > >--------------------------------------------------- >To unsubscribe from this group, send an email to: >68300-unsubscribe@yahoogroups.com > >To learn more about Motorola Microcontrollers, please visit >http://www.motorola.com/mcu > > > >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ = = = = = = = = = = = = = = = = = = = = \ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd \ufffd\ufffd \ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffdliubo \ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffdboliu@... \ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd2003-09-13