|HP41CL physical ports -or- how many physical ports do you require with the HP41CL?|
Message #1 Posted by Geoff Quickfall on 21 June 2011, 6:18 p.m.
More 41CL stuff!
When looking at the physical use of ports on the CL many users have questioned whether installing the time module internally and/or moving the RS232 jack to another location (side) would make more sense.
My short answer would be yes IF the free physical ports are required. Remember, all the existing ROMs are available on the CL board and can be invoked by the CL plug commands. There are a few exceptions such as the timer module and others listed in the manual:
HP 41CL home page
With this in mind do you NEED to internalize the time module or move the rs232 jack?
Again from the manual, the time module is physically installed in any PORT, although PORT two is the most convenient for me. It leaves PORT three for the IR or HPIL modules. Physical PORT four is for the card reader (PORT 4 LOWER must remain free as the card reader functions install in PORT 4 LOWER).
The following is the basic physical configuration:
table 1: Free ports with time module and RS232 jack in place:
PORT 1 UPPER FREE
PORT 1 LOWER YNFS (CL functions required, see manual)
PORT 2 UPPER FREE
PORT 3 LOWER FREE
PORT 4 UPPER FREE
PORT 4 LOWER FREE
figure 1: Basic configuration.
As you can see from table 1 the RS232 jack and the time module take no PORTs away from ROM image use. PORT 1 LOWER is taken over by the CL board for functions as does any physical module which takes over specific addresses. This still leaves PORT 1 UPPER free for STAT or any other ROM image occupying less then half a page.
The timer module behaves the same. Although the physical port is taken up, it does not occupy PORT 2 therefore leaving it free for a ROM image such as the full page ADVANTAGE module.
So you are left with two physical ports for physical module use. In figure 2 the IR module has been removed for the HPIL module. If using the HPIL to drive an HPIL printer then the IR module should be removed. If you are using the IR module with the HPIL then the HPIL module should have the printer switch set to disabled. (edited to reflect Montes' reminder that the HPIL module HAS a printer enable, disable switch.)
Figure 2. IR removed and HPIL installed with Disc drive:
In figure 3 the HP 41CL now has the HPIL and the Card Reader installed and linked to the HPIL cassette:
So now two free physical ports contain the HPIL and the card reader.
The calculator is currently configured with the following physical modules and ROM images:
Table 2: VIRTUAL STATUS (non phyical ROM images):
PORT 1 UPPER STAT
PORT 1 LOWER YNFS
PORT 2 UPPER FREE
PORT 2 LOWER FREE
PORT 3 UPPER PPC
PORT 3 LOWER CCD OS\X
PORT 4 UPPER FREE
PORT 4 LOWER CARD READER functions
Table 3: PHYSICAL STATUS (physically inserted modules)
PORT 1 RS232 JACK technically not a ROM at all as it just
occupies the space.
PORT 2 TIME MODULE
PORT 3 IR MODULE swappable with HPIL or others
PORT 4 CARD READER requires PORT 4 LOWER be free of virtual ROM
I cannot foresee any need to free up physically the two upper PORTs; 1 and 2. Esthetically I like the RS232 jack in place as it keeps the calculator case free of modification. But that is my opinion.
Of course there may be a reason or use by some one else that requires more then 2 open ports be available. So unless someone comes up with a valid reason to open up the two upper ports I say leave well enough alone ;-)
Just some ramblings (due in part between the CL users to internalize the timer module and move the RS232 Jack).
long live the CL (boy is it fast in turbo50!!!!)
Figure 4: overlay and modules, early photo, move the IR to PORT 3 in your mind please!
Edited: 22 June 2011, 6:05 p.m. after one or more responses were posted