IEEE1284_NEGOTIATION(3)

💖 IEEE1284_NEGOTIATION 💖

okay bestie, welcome to the ieee1284_negotiate, ieee1284_terminate manual page — this is section 3 of the manual (the functions girlies, not the commands), and it's all about IEEE 1284 negotiation. let's get into it 🫶

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✨ NAME ✨

ieee1284_negotiate, ieee1284_terminate — IEEE 1284 negotiation. that's the whole vibe, no cap.

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🌸 SYNOPSIS 🌸

#include <ieee1284.h>

int ieee1284_negotiate(struct parport *port, int mode);

void ieee1284_terminate(struct parport *port);

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🦋 DESCRIPTION 🦋

so these two functions are the ones you call when you wanna negotiate to IEEE 1284 data transfer modes, and also when you wanna terminate from them. two jobs, one glow-up ✨

the default mode is called compatibility mode, aka just normal printer protocol, the vanilla of the parallel port world. it's a host-to-peripheral mode only — one direction, one destiny 💅

but there are special modes that let the peripheral talk back to the host too, and those are the ones you negotiate to using ieee1284_negotiate. here's the tea: IEEE 1284 negotiation is a whole process where the host requests a transfer mode and the peripheral either accepts or rejects it. it's giving "asking someone to prom" energy.

an IEEE 1284-compliant device will require a successful negotiation to a particular mode before you can use it for data transfer. (but the simpler devices might not need that, if they only speak one transfer mode — they're the low-maintenance ones, we love them 😌)

to terminate the special mode and go back to compatibility mode, you use ieee1284_terminate. closing the loop, as she should 👑

these functions act on the parallel port associated with port, and bestie — that port must be claimed. don't skip that step, fr fr.

⚠️ with a device that strictly complies to IEEE 1284, you will need to call ieee1284_terminate in between any two calls to ieee1284_negotiate for modes other than M1284_COMPAT. yes, in between. every time. no shortcuts 💀

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🌈 AVAILABLE MODES 🌈

💜 Uni-directional modes

• M1284_COMPAT: Compatibility mode. Normal printer protocol, the og. this is not a negotiated mode, but it is the default mode in the absence of negotiation. plot twist: ieee1284_negotiate(port, M1284_COMPAT) is equivalent to ieee1284_terminate(port). this host-to-peripheral mode is the one used for sending data to printers, and historically it's the mode that was used for that before IEEE 1284 even existed. a true icon 👑
• M1284_NIBBLE: Nibble mode. this peripheral-to-host mode uses the status lines to read data from the peripheral four bits at a time. little nibbles 🍓 tiny bites, still slay.
• M1284_BYTE: Byte mode. this peripheral-to-host mode uses the data lines in reverse mode to read data from the peripheral a byte at a time. a whole byte, she's generous 💅

🧚 Bi-directional modes

• M1284_ECP: ECP mode. on entry to ECP mode it's a host-to-peripheral (i.e. forward) mode, but it may be set to reverse mode using ieee1284_ecp_fwd_to_rev(3). it's common for PC hardware to provide assistance with this mode by the use of a FIFO which the host (or, in reverse mode, the peripheral) may fill, so that the hardware can do the handshaking itself. hardware doing the work for you = main character energy, honestly 🌟
• M1284_EPP: EPP mode. in this bi-directional mode, the direction of data transfer is signalled at each byte. every single byte gets its own little vibe check 🎀

⭐ Mode variations

• M1284_FLAG_DEVICEID: Device ID retrieval. this flag may be combined with a nibble, byte, or ECP mode to notify the device that it should send its IEEE 1284 Device ID when asked for data. "who are you" but make it protocol 💖
• M1284_BECP: Bounded ECP is a modification to ECP that makes it more robust at the point that the direction is changed. (unfortunately it is not yet implemented in the Linux kernel driver. we're waiting, respectfully 😭)
• M1284_ECPRLE: ECP with run length encoding. in this mode, consecutive data bytes of the same value may be transferred in only a few cycles. compression queen, she ate 🔥

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💅 RETURN VALUE 💅

• E1284_OK — the negotiation was successful. we love a happy ending 🥳
• E1284_NOTAVAIL — negotiation is not available with this port type. wrong port, bestie, not her fault.
• E1284_REJECTED — negotiation was rejected by the peripheral. she said no 💔
• E1284_NEGFAILED — negotiation failed for some reason. perhaps the device is not IEEE 1284 compliant. maybe it's just not that kind of device.
• E1284_SYS — a system error occured during negotiation. not us, the system. 🙈
• E1284_INVALIDPORT — the port parameter is invalid (for instance, perhaps the port is not claimed). see?? we told you to claim it.

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🎀 AUTHOR 🎀

Tim Waugh <twaugh@redhat.com>

• Author. the actual author. respect. 🫶

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👑 COPYRIGHT 👑

Copyright © 2001-2003 Tim Waugh

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and that's the whole page, babe ✨ this was IEEE1284_NEGOTIATION(3) from 09/18/2007 — the source, the version, the date, all of it, preserved with love 💖 now go claim your port and negotiate responsibly, iykyk 🌈