1 files changed, 30 insertions, 0 deletions

diff --git a/embassy-usb-synopsys-otg/src/lib.rs b/embassy-usb-synopsys-otg/src/lib.rs
index 5fb82db42..b145f4aa8 100644
--- a/embassy-usb-synopsys-otg/src/lib.rs
+++ b/embassy-usb-synopsys-otg/src/lib.rs
@@ -1071,6 +1071,21 @@ impl<'d> embassy_usb_driver::EndpointOut for Endpoint<'d, Out> {
                         w.set_pktcnt(1);
                     });
 
+                    if self.info.ep_type == EndpointType::Isochronous {
+                        // Isochronous endpoints must set the correct even/odd frame bit to
+                        // correspond with the next frame's number.
+                        let frame_number = self.regs.dsts().read().fnsof();
+                        let frame_is_odd = frame_number & 0x01 == 1;
+
+                        self.regs.doepctl(index).modify(|r| {
+                            if frame_is_odd {
+                                r.set_sd0pid_sevnfrm(true);
+                            } else {
+                                r.set_sd1pid_soddfrm(true);
+                            }
+                        });
+                    }
+
                     // Clear NAK to indicate we are ready to receive more data
                     self.regs.doepctl(index).modify(|w| {
                         w.set_cnak(true);
@@ -1158,6 +1173,21 @@ impl<'d> embassy_usb_driver::EndpointIn for Endpoint<'d, In> {
                 w.set_xfrsiz(buf.len() as _);
             });
 
+            if self.info.ep_type == EndpointType::Isochronous {
+                // Isochronous endpoints must set the correct even/odd frame bit to
+                // correspond with the next frame's number.
+                let frame_number = self.regs.dsts().read().fnsof();
+                let frame_is_odd = frame_number & 0x01 == 1;
+
+                self.regs.diepctl(index).modify(|r| {
+                    if frame_is_odd {
+                        r.set_sd0pid_sevnfrm(true);
+                    } else {
+                        r.set_sd1pid_soddfrm(true);
+                    }
+                });
+            }
+
             // Enable endpoint
             self.regs.diepctl(index).modify(|w| {
                 w.set_cnak(true);